From af4ad3bf330a60fc6ee2dcab6a2b8953cd300a20 Mon Sep 17 00:00:00 2001
From: Fabio Caccamo <fabio.caccamo@gmail.com>
Date: Wed, 1 Feb 2023 13:53:50 +0100
Subject: [PATCH 1/6] Add `mypy` to CI.

---
 .github/workflows/test-package.yml | 8 ++++++++
 requirements-test.txt              | 1 +
 setup.cfg                          | 5 +++++
 tox.ini                            | 1 +
 4 files changed, 15 insertions(+)

diff --git a/.github/workflows/test-package.yml b/.github/workflows/test-package.yml
index 443ec916..416ed6c3 100644
--- a/.github/workflows/test-package.yml
+++ b/.github/workflows/test-package.yml
@@ -33,6 +33,14 @@ jobs:
         pip install -r requirements.txt
         pip install -r requirements-test.txt
 
+    - name: Run pre-commit
+      run: |
+        pre-commit run -a
+
+    - name: Run mypy
+      run: |
+        mypy --install-types --non-interactive
+
     - name: Run tests
       run: |
         coverage run --append --source=benedict -m unittest
diff --git a/requirements-test.txt b/requirements-test.txt
index d8fac991..9d7f9702 100644
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -1,5 +1,6 @@
 coverage == 7.1.*
 orjson == 3.8.*
+mypy == 0.991
 pre-commit == 3.0.*
 python-decouple == 3.7
 tox == 4.4.*
diff --git a/setup.cfg b/setup.cfg
index 1a3d4b89..2ab0af25 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -123,3 +123,8 @@ ignore = E501, W503
 max-line-length = 89
 max-complexity = 10
 select = B,C,E,F,W,T4,B9
+
+[mypy]
+files = benedict
+ignore_missing_imports = True
+strict = True
diff --git a/tox.ini b/tox.ini
index ac7d89b6..d9c36c0e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,5 +17,6 @@ deps =
 
 commands =
     pre-commit run -a
+    mypy --install-types --non-interactive
     coverage run --append -m unittest discover
     coverage report --show-missing --ignore-errors

From f82d629868f6f6fec8e55a11a4aaaa4efa5ebc9a Mon Sep 17 00:00:00 2001
From: Fabio Caccamo <fabio.caccamo@gmail.com>
Date: Wed, 1 Feb 2023 13:54:35 +0100
Subject: [PATCH 2/6] Run tests with `unittest discover`.

---
 .github/workflows/test-package.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test-package.yml b/.github/workflows/test-package.yml
index 416ed6c3..06645375 100644
--- a/.github/workflows/test-package.yml
+++ b/.github/workflows/test-package.yml
@@ -43,7 +43,8 @@ jobs:
 
     - name: Run tests
       run: |
-        coverage run --append --source=benedict -m unittest
+        coverage run --append -m unittest discover
+        coverage report --show-missing
         coverage xml -o ./coverage.xml
 
     - name: Upload coverage to Codecov

From d29e97438395414f5c7388cc7a067919352c384c Mon Sep 17 00:00:00 2001
From: Fabio Caccamo <fabio.caccamo@gmail.com>
Date: Wed, 1 Feb 2023 15:46:52 +0100
Subject: [PATCH 3/6] Improve tests.

---
 tests/__init__.py                  |  4 ----
 tests/aws.py                       | 20 +++++++++++++++++++
 tests/dicts/base/test_base_dict.py | 11 -----------
 tests/dicts/io/test_io_dict_xls.py | 19 +++++++-----------
 tests/dicts/io/test_io_util.py     | 16 +++++----------
 tests/dicts/test_benedict.py       | 25 ++----------------------
 tests/github/test_issue_0020.py    |  3 ---
 tests/github/test_issue_0198.py    | 31 ++++++++++--------------------
 8 files changed, 44 insertions(+), 85 deletions(-)
 create mode 100644 tests/aws.py

diff --git a/tests/__init__.py b/tests/__init__.py
index fba0404a..e69de29b 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -1,4 +0,0 @@
-import unittest
-
-if __name__ == "__main__":
-    unittest.main()
diff --git a/tests/aws.py b/tests/aws.py
new file mode 100644
index 00000000..d0c93ee9
--- /dev/null
+++ b/tests/aws.py
@@ -0,0 +1,20 @@
+from decouple import config
+
+
+def get_aws_credentials():
+    aws_access_key_id = config("AWS_ACCESS_KEY_ID", default=None)
+    aws_secret_access_key = config("AWS_SECRET_ACCESS_KEY", default=None)
+    return aws_access_key_id, aws_secret_access_key
+
+
+def get_aws_credentials_options():
+    aws_access_key_id, aws_secret_access_key = get_aws_credentials()
+    return {
+        "aws_access_key_id": aws_access_key_id,
+        "aws_secret_access_key": aws_secret_access_key,
+    }
+
+
+def has_aws_credentials():
+    aws_access_key_id, aws_secret_access_key = get_aws_credentials()
+    return all([aws_access_key_id, aws_secret_access_key])
diff --git a/tests/dicts/base/test_base_dict.py b/tests/dicts/base/test_base_dict.py
index 5369b332..79d7c9a4 100644
--- a/tests/dicts/base/test_base_dict.py
+++ b/tests/dicts/base/test_base_dict.py
@@ -224,17 +224,6 @@ def test__str__with_pointer(self):
         self.assertEqual(str(d), str(b))
         self.assertEqual(b, b.dict())
 
-    @unittest.skipIf(sys.version_info[0] > 2, "No unicode in Python 3")
-    def test__unicode__(self):
-        d = BaseDict()
-        d["name"] = "pythòn-bènèdìçt"
-        # print(unicode(d))
-
-    @unittest.skipIf(sys.version_info[0] > 2, "No unicode in Python > 2")
-    def test__unicode__with_pointer(self):
-        d = BaseDict({"name": "pythòn-bènèdìçt"})
-        # print(unicode(d))
-
     def test_clear(self):
         d = {
             "a": 1,
diff --git a/tests/dicts/io/test_io_dict_xls.py b/tests/dicts/io/test_io_dict_xls.py
index 8955b51a..c2332154 100644
--- a/tests/dicts/io/test_io_dict_xls.py
+++ b/tests/dicts/io/test_io_dict_xls.py
@@ -1,8 +1,8 @@
-from decouple import config
+import unittest
 
 from benedict.dicts.io import IODict
-
-from .test_io_dict import io_dict_test_case
+from tests.aws import get_aws_credentials_options, has_aws_credentials
+from tests.dicts.io.test_io_dict import io_dict_test_case
 
 
 class io_dict_xls_test_case(io_dict_test_case):
@@ -119,16 +119,11 @@ def test_from_xls_with_valid_url_valid_content(self):
                 self.assertTrue(isinstance(d, dict))
                 self.assertEqual(d, expected_dict)
 
+    @unittest.skipUnless(
+        has_aws_credentials(), "Skip because aws credentials are not set."
+    )
     def test_from_xls_with_valid_s3_url_valid_content(self):
-        aws_access_key_id = config("AWS_ACCESS_KEY_ID", default=None)
-        aws_secret_access_key = config("AWS_SECRET_ACCESS_KEY", default=None)
-        if not all([aws_access_key_id, aws_secret_access_key]):
-            # don't use s3 on GH CI
-            return
-        s3_options = {
-            "aws_access_key_id": aws_access_key_id,
-            "aws_secret_access_key": aws_secret_access_key,
-        }
+        s3_options = get_aws_credentials_options()
         expected_dict = {
             "values": [
                 {
diff --git a/tests/dicts/io/test_io_util.py b/tests/dicts/io/test_io_util.py
index d8001051..e1571d01 100644
--- a/tests/dicts/io/test_io_util.py
+++ b/tests/dicts/io/test_io_util.py
@@ -1,8 +1,7 @@
 import unittest
 
-from decouple import config
-
 from benedict.dicts.io import io_util
+from tests.aws import get_aws_credentials_options, has_aws_credentials
 
 
 class io_util_test_case(unittest.TestCase):
@@ -87,16 +86,11 @@ def test_write_file_to_s3(self):
         # io_util.write_file_to_s3("s3://test-bucket/my-file.txt", "ok", anon=True)
         pass
 
+    @unittest.skipUnless(
+        has_aws_credentials(), "Skip because aws credentials are not set."
+    )
     def test_write_and_read_content_s3(self):
-        aws_access_key_id = config("AWS_ACCESS_KEY_ID", default=None)
-        aws_secret_access_key = config("AWS_SECRET_ACCESS_KEY", default=None)
-        if not all([aws_access_key_id, aws_secret_access_key]):
-            # skip s3 on GH CI
-            return
-        s3_options = {
-            "aws_access_key_id": aws_access_key_id,
-            "aws_secret_access_key": aws_secret_access_key,
-        }
+        s3_options = get_aws_credentials_options()
         filepath = "s3://python-benedict/test-io.txt"
         io_util.write_content_to_s3(filepath, "ok", s3_options=s3_options)
         content = io_util.read_content_from_s3(filepath, s3_options=s3_options)
diff --git a/tests/dicts/test_benedict.py b/tests/dicts/test_benedict.py
index 5ea37db1..4610fa91 100644
--- a/tests/dicts/test_benedict.py
+++ b/tests/dicts/test_benedict.py
@@ -370,7 +370,7 @@ def test_filter_with_parse(self):
         self.assertEqual(f, r)
         self.assertTrue(isinstance(f, benedict))
 
-    def test_filter(self):
+    def test_find(self):
         d = {
             "a": 1,
             "b": 2,
@@ -727,30 +727,9 @@ def test_from_yaml_with_keypath_separator_in_keys(self):
         with self.assertRaises(ValueError):
             # static method
             d = benedict.from_yaml(j)
-            self.assertTrue(isinstance(d, dict))
-            self.assertEqual(
-                d,
-                {
-                    "a": 1,
-                    "b": {
-                        "c": 3,
-                        "d": 4,
-                    },
-                },
-            )
+        with self.assertRaises(ValueError):
             # constructor
             d = benedict(j, format="yaml")
-            self.assertTrue(isinstance(d, dict))
-            self.assertEqual(
-                d,
-                {
-                    "a": 1,
-                    "b": {
-                        "c": 3,
-                        "d": 4,
-                    },
-                },
-            )
         r = {
             "192.168.0.1": {
                 "test": "value",
diff --git a/tests/github/test_issue_0020.py b/tests/github/test_issue_0020.py
index 6de21669..d3d7389f 100644
--- a/tests/github/test_issue_0020.py
+++ b/tests/github/test_issue_0020.py
@@ -15,9 +15,6 @@ def __init__(self, val):
     def from_yaml(cls, loader, node):
         return cls(node.value)
 
-    def __repr__(self):
-        return f"GetAtt({self.val})"
-
 
 yaml.add_constructor("!GetAtt", GetAtt.from_yaml)
 
diff --git a/tests/github/test_issue_0198.py b/tests/github/test_issue_0198.py
index 04a4a572..7f6e3c54 100644
--- a/tests/github/test_issue_0198.py
+++ b/tests/github/test_issue_0198.py
@@ -1,8 +1,7 @@
 import unittest
 
-from decouple import config
-
 from benedict import benedict
+from tests.aws import get_aws_credentials_options, has_aws_credentials
 
 
 class github_issue_0198_test_case(unittest.TestCase):
@@ -14,33 +13,23 @@ class github_issue_0198_test_case(unittest.TestCase):
     - Run python -m unittest tests.github.test_issue_0198
     """
 
+    @unittest.skipUnless(
+        has_aws_credentials(), "Skip because aws credentials are not set."
+    )
     def test_constructor_with_s3_url_and_s3_options_with_file_json(self):
-        aws_access_key_id = config("AWS_ACCESS_KEY_ID", default=None)
-        aws_secret_access_key = config("AWS_SECRET_ACCESS_KEY", default=None)
-        if not all([aws_access_key_id, aws_secret_access_key]):
-            # don't use s3 on GH CI
-            return
-        s3_options = {
-            "aws_access_key_id": aws_access_key_id,
-            "aws_secret_access_key": aws_secret_access_key,
-        }
+        s3_options = get_aws_credentials_options()
         d = benedict(
             "s3://python-benedict/valid-content.json",
-            s3_options=s3_options,
+            s3_options=get_aws_credentials_options(),
         )
         expected_dict = {"a": 1, "b": 2, "c": 3, "x": 7, "y": 8, "z": 9}
         self.assertEqual(d, expected_dict)
 
+    @unittest.skipUnless(
+        has_aws_credentials(), "Skip because aws credentials are not set."
+    )
     def test_constructor_with_s3_url_and_s3_options_with_file_xlsx(self):
-        aws_access_key_id = config("AWS_ACCESS_KEY_ID", default=None)
-        aws_secret_access_key = config("AWS_SECRET_ACCESS_KEY", default=None)
-        if not all([aws_access_key_id, aws_secret_access_key]):
-            # don't use s3 on GH CI
-            return
-        s3_options = {
-            "aws_access_key_id": aws_access_key_id,
-            "aws_secret_access_key": aws_secret_access_key,
-        }
+        s3_options = get_aws_credentials_options()
         d = benedict(
             "s3://python-benedict/valid-content.xlsx",
             s3_options=s3_options,

From acb60ec1817857a01e7d9d05a4735e8349de543f Mon Sep 17 00:00:00 2001
From: Fabio Caccamo <fabio.caccamo@gmail.com>
Date: Wed, 1 Feb 2023 15:48:35 +0100
Subject: [PATCH 4/6] Start adding type hints.

---
 benedict/core/clean.py                 |  4 +-
 benedict/core/clone.py                 |  3 +-
 benedict/core/dump.py                  |  4 +-
 benedict/core/filter.py                |  6 ++-
 benedict/core/flatten.py               | 10 ++---
 benedict/core/invert.py                |  8 ++--
 benedict/core/items_sorted.py          |  6 +--
 benedict/core/keylists.py              |  2 +-
 benedict/core/keypaths.py              |  4 +-
 benedict/core/match.py                 |  2 +-
 benedict/core/merge.py                 |  8 ++--
 benedict/core/move.py                  |  2 +-
 benedict/core/nest.py                  |  2 +-
 benedict/core/remove.py                |  2 +-
 benedict/core/rename.py                |  2 +-
 benedict/core/search.py                | 13 +++++--
 benedict/core/standardize.py           |  4 +-
 benedict/core/swap.py                  |  2 +-
 benedict/core/traverse.py              |  8 ++--
 benedict/core/unflatten.py             |  4 +-
 benedict/core/unique.py                |  2 +-
 benedict/dicts/__init__.py             |  9 +++--
 benedict/dicts/base/base_dict.py       |  6 ++-
 benedict/dicts/io/io_dict.py           | 52 +++++++++++++-------------
 benedict/dicts/io/io_util.py           | 37 ++++++++++--------
 benedict/dicts/keylist/keylist_dict.py | 14 ++++---
 benedict/dicts/keypath/keypath_dict.py | 16 ++++----
 benedict/dicts/parse/parse_dict.py     | 27 ++++++-------
 benedict/dicts/parse/parse_util.py     |  5 ++-
 benedict/py.typed                      |  0
 benedict/serializers/__init__.py       |  2 +-
 benedict/serializers/abstract.py       | 11 ++++--
 benedict/serializers/base64.py         | 21 ++++++-----
 benedict/serializers/csv.py            |  5 ++-
 benedict/serializers/ini.py            |  5 ++-
 benedict/serializers/json.py           |  5 ++-
 benedict/serializers/pickle.py         |  5 ++-
 benedict/serializers/plist.py          |  5 ++-
 benedict/serializers/query_string.py   |  9 +++--
 benedict/serializers/toml.py           |  6 ++-
 benedict/serializers/xls.py            | 18 +++++----
 benedict/serializers/xml.py            |  6 ++-
 benedict/serializers/yaml.py           |  6 ++-
 benedict/utils/type_util.py            | 45 +++++++++++-----------
 44 files changed, 233 insertions(+), 180 deletions(-)
 create mode 100644 benedict/py.typed

diff --git a/benedict/core/clean.py b/benedict/core/clean.py
index da1b6d0e..ef0e620b 100644
--- a/benedict/core/clean.py
+++ b/benedict/core/clean.py
@@ -1,7 +1,7 @@
 from benedict.utils import type_util
 
 
-def _clean_item(d, key, strings, collections):
+def _clean_item(d, key, strings: bool, collections: bool):
     value = d.get(key, None)
     if not value:
         del_none = value is None
@@ -12,7 +12,7 @@ def _clean_item(d, key, strings, collections):
     return False
 
 
-def clean(d, strings=True, collections=True):
+def clean(d, strings: bool = True, collections: bool = True):
     keys = list(d.keys())
     for key in keys:
         if _clean_item(d, key, strings, collections):
diff --git a/benedict/core/clone.py b/benedict/core/clone.py
index ed34f84f..aa3b8c86 100644
--- a/benedict/core/clone.py
+++ b/benedict/core/clone.py
@@ -1,7 +1,8 @@
 import copy
+from typing import Any, Dict, Optional
 
 
-def clone(obj, empty=False, memo=None):
+def clone(obj, empty: bool = False, memo: Optional[Dict[int, Any]] = None):
     d = copy.deepcopy(obj, memo)
     if empty:
         d.clear()
diff --git a/benedict/core/dump.py b/benedict/core/dump.py
index 735ffe70..c6117ef3 100644
--- a/benedict/core/dump.py
+++ b/benedict/core/dump.py
@@ -1,7 +1,9 @@
+from typing import Any
+
 from benedict.serializers import JSONSerializer
 
 
-def dump(obj, **kwargs):
+def dump(obj: Any, **kwargs: Any) -> str:
     serializer = JSONSerializer()
     options = {"indent": 4, "sort_keys": True}
     options.update(**kwargs)
diff --git a/benedict/core/filter.py b/benedict/core/filter.py
index d823a576..a745aacb 100644
--- a/benedict/core/filter.py
+++ b/benedict/core/filter.py
@@ -1,7 +1,9 @@
-from benedict.core import clone
+from typing import Any, Callable
 
+from benedict.core.clone import clone
 
-def filter(d, predicate):
+
+def filter(d, predicate: Callable[[Any, Any], bool]):
     if not callable(predicate):
         raise ValueError("predicate argument must be a callable.")
     new_dict = clone(d, empty=True)
diff --git a/benedict/core/flatten.py b/benedict/core/flatten.py
index 9d119c65..a8311641 100644
--- a/benedict/core/flatten.py
+++ b/benedict/core/flatten.py
@@ -1,14 +1,14 @@
-from benedict.core import clone
+from benedict.core.clone import clone
 from benedict.utils import type_util
 
 
-def _flatten_key(base_key, key, separator):
+def _flatten_key(base_key: str, key, separator: str) -> str:
     if base_key and separator:
         return f"{base_key}{separator}{key}"
-    return key
+    return f"{key}"
 
 
-def _flatten_item(d, base_dict, base_key, separator):
+def _flatten_item(d, base_dict, base_key, separator: str):
     new_dict = base_dict
     keys = list(d.keys())
     for key in keys:
@@ -26,6 +26,6 @@ def _flatten_item(d, base_dict, base_key, separator):
     return new_dict
 
 
-def flatten(d, separator="_"):
+def flatten(d, separator: str = "_"):
     new_dict = clone(d, empty=True)
     return _flatten_item(d, base_dict=new_dict, base_key="", separator=separator)
diff --git a/benedict/core/invert.py b/benedict/core/invert.py
index 6d33f4e9..88f8030c 100644
--- a/benedict/core/invert.py
+++ b/benedict/core/invert.py
@@ -1,20 +1,20 @@
-from benedict.core import clone
+from benedict.core.clone import clone
 from benedict.utils import type_util
 
 
-def _invert_item(d, key, value, flat):
+def _invert_item(d, key, value, flat: bool) -> None:
     if flat:
         d.setdefault(value, key)
     else:
         d.setdefault(value, []).append(key)
 
 
-def _invert_list(d, key, value, flat):
+def _invert_list(d, key, value, flat: bool) -> None:
     for value_item in value:
         _invert_item(d, key, value_item, flat)
 
 
-def invert(d, flat=False):
+def invert(d, flat: bool = False):
     new_dict = clone(d, empty=True)
     for key, value in d.items():
         if type_util.is_list_or_tuple(value):
diff --git a/benedict/core/items_sorted.py b/benedict/core/items_sorted.py
index 4237ffe2..b06fdba9 100644
--- a/benedict/core/items_sorted.py
+++ b/benedict/core/items_sorted.py
@@ -1,10 +1,10 @@
-def _items_sorted_by_item_at_index(d, index, reverse):
+def _items_sorted_by_item_at_index(d, index, reverse: bool):
     return sorted(d.items(), key=lambda item: item[index], reverse=reverse)
 
 
-def items_sorted_by_keys(d, reverse=False):
+def items_sorted_by_keys(d, reverse: bool = False):
     return _items_sorted_by_item_at_index(d, 0, reverse)
 
 
-def items_sorted_by_values(d, reverse=False):
+def items_sorted_by_values(d, reverse: bool = False):
     return _items_sorted_by_item_at_index(d, 1, reverse)
diff --git a/benedict/core/keylists.py b/benedict/core/keylists.py
index 9d516dd8..6d928a95 100644
--- a/benedict/core/keylists.py
+++ b/benedict/core/keylists.py
@@ -28,5 +28,5 @@ def _get_keylist_for_value(value, parent_keys, indexes):
     return []
 
 
-def keylists(d, indexes=False):
+def keylists(d, indexes: bool = False):
     return _get_keylist_for_value(d, [], indexes)
diff --git a/benedict/core/keypaths.py b/benedict/core/keypaths.py
index 1785f926..7b32dd99 100644
--- a/benedict/core/keypaths.py
+++ b/benedict/core/keypaths.py
@@ -1,8 +1,10 @@
+from typing import List
+
 from benedict.core.keylists import keylists
 from benedict.utils import type_util
 
 
-def keypaths(d, separator=".", indexes=False):
+def keypaths(d, separator: str = ".", indexes: bool = False) -> List[str]:
     separator = separator or "."
     if not type_util.is_string(separator):
         raise ValueError("separator argument must be a (non-empty) string.")
diff --git a/benedict/core/match.py b/benedict/core/match.py
index 53643c74..b9b07ec6 100644
--- a/benedict/core/match.py
+++ b/benedict/core/match.py
@@ -4,7 +4,7 @@
 from benedict.utils import type_util
 
 
-def match(d, pattern, separator=".", indexes=True):
+def match(d, pattern, separator: str = ".", indexes: bool = True):
     if type_util.is_regex(pattern):
         regex = pattern
     elif type_util.is_string(pattern):
diff --git a/benedict/core/merge.py b/benedict/core/merge.py
index 0156e675..d1f8f3b5 100644
--- a/benedict/core/merge.py
+++ b/benedict/core/merge.py
@@ -1,12 +1,14 @@
+from typing import Any
+
 from benedict.utils import type_util
 
 
-def _merge_dict(d, other, overwrite=True, concat=False):
+def _merge_dict(d, other, overwrite: bool = True, concat: bool = False) -> None:
     for key, value in other.items():
         _merge_item(d, key, value, overwrite=overwrite, concat=concat)
 
 
-def _merge_item(d, key, value, overwrite=True, concat=False):
+def _merge_item(d, key, value, overwrite: bool = True, concat: bool = False) -> None:
     if key in d:
         item = d.get(key, None)
         if type_util.is_dict(item) and type_util.is_dict(value):
@@ -19,7 +21,7 @@ def _merge_item(d, key, value, overwrite=True, concat=False):
         d[key] = value
 
 
-def merge(d, other, *args, **kwargs):
+def merge(d, other, *args, **kwargs: Any):
     overwrite = kwargs.get("overwrite", True)
     concat = kwargs.get("concat", False)
     others = [other] + list(args)
diff --git a/benedict/core/move.py b/benedict/core/move.py
index 4bd62fdd..1232380b 100644
--- a/benedict/core/move.py
+++ b/benedict/core/move.py
@@ -1,4 +1,4 @@
-def move(d, key_src, key_dest, overwrite=True):
+def move(d, key_src, key_dest, overwrite: bool = True) -> None:
     if key_dest == key_src:
         return
     if key_dest in d and not overwrite:
diff --git a/benedict/core/nest.py b/benedict/core/nest.py
index 1f13930c..6a544a43 100644
--- a/benedict/core/nest.py
+++ b/benedict/core/nest.py
@@ -1,7 +1,7 @@
 from benedict.core.groupby import groupby
 
 
-def _nest_items(nested_items, item, id_key, children_key):
+def _nest_items(nested_items, item, id_key, children_key) -> None:
     children_items = nested_items.pop(item[id_key], [])
     item[children_key] = children_items
     for child_item in children_items:
diff --git a/benedict/core/remove.py b/benedict/core/remove.py
index d68838f2..09368aed 100644
--- a/benedict/core/remove.py
+++ b/benedict/core/remove.py
@@ -1,7 +1,7 @@
 from benedict.utils import type_util
 
 
-def remove(d, keys, *args):
+def remove(d, keys, *args) -> None:
     if type_util.is_string(keys):
         keys = [keys]
     keys += args
diff --git a/benedict/core/rename.py b/benedict/core/rename.py
index a616fc67..47a3457a 100644
--- a/benedict/core/rename.py
+++ b/benedict/core/rename.py
@@ -1,5 +1,5 @@
 from benedict.core.move import move
 
 
-def rename(d, key, key_new):
+def rename(d, key, key_new) -> None:
     move(d, key, key_new, overwrite=False)
diff --git a/benedict/core/search.py b/benedict/core/search.py
index 34637246..50a7a560 100644
--- a/benedict/core/search.py
+++ b/benedict/core/search.py
@@ -2,13 +2,13 @@
 from benedict.utils import type_util
 
 
-def _get_term(value, case_sensitive):
+def _get_term(value, case_sensitive: bool):
     v_is_str = type_util.is_string(value)
     v = value.lower() if (v_is_str and not case_sensitive) else value
     return (v, v_is_str)
 
 
-def _get_match(query, value, exact, case_sensitive):
+def _get_match(query, value, exact: bool, case_sensitive: bool) -> bool:
     q, q_is_str = _get_term(query, case_sensitive)
     v, v_is_str = _get_term(value, case_sensitive)
     # TODO: add regex support
@@ -17,7 +17,14 @@ def _get_match(query, value, exact, case_sensitive):
     return q == v
 
 
-def search(d, query, in_keys=True, in_values=True, exact=False, case_sensitive=True):
+def search(
+    d,
+    query,
+    in_keys: bool = True,
+    in_values: bool = True,
+    exact: bool = False,
+    case_sensitive: bool = True,
+):
     items = []
 
     def _search_item(item_dict, item_key, item_value):
diff --git a/benedict/core/standardize.py b/benedict/core/standardize.py
index d255ad66..4a1314d0 100644
--- a/benedict/core/standardize.py
+++ b/benedict/core/standardize.py
@@ -7,7 +7,7 @@
 from benedict.utils import type_util
 
 
-def _standardize_item(d, key, value):
+def _standardize_item(d, key, value) -> None:
     if type_util.is_string(key):
         # https://stackoverflow.com/a/12867228/2096218
         norm_key = re.sub(r"((?<=[a-z0-9])[A-Z]|(?!^)[A-Z](?=[a-z]))", r"_\1", key)
@@ -15,5 +15,5 @@ def _standardize_item(d, key, value):
         rename(d, key, norm_key)
 
 
-def standardize(d):
+def standardize(d) -> None:
     traverse(d, _standardize_item)
diff --git a/benedict/core/swap.py b/benedict/core/swap.py
index 5c6e5d79..d204d85b 100644
--- a/benedict/core/swap.py
+++ b/benedict/core/swap.py
@@ -1,4 +1,4 @@
-def swap(d, key1, key2):
+def swap(d, key1, key2) -> None:
     if key1 == key2:
         return
     val1 = d[key1]
diff --git a/benedict/core/traverse.py b/benedict/core/traverse.py
index 8019b235..555cf073 100644
--- a/benedict/core/traverse.py
+++ b/benedict/core/traverse.py
@@ -1,14 +1,14 @@
 from benedict.utils import type_util
 
 
-def _traverse_collection(d, callback):
+def _traverse_collection(d, callback) -> None:
     if type_util.is_dict(d):
         _traverse_dict(d, callback)
     elif type_util.is_list_or_tuple(d):
         _traverse_list(d, callback)
 
 
-def _traverse_dict(d, callback):
+def _traverse_dict(d, callback) -> None:
     keys = list(d.keys())
     for key in keys:
         value = d.get(key, None)
@@ -16,14 +16,14 @@ def _traverse_dict(d, callback):
         _traverse_collection(value, callback)
 
 
-def _traverse_list(ls, callback):
+def _traverse_list(ls, callback) -> None:
     items = list(enumerate(ls))
     for index, value in items:
         callback(ls, index, value)
         _traverse_collection(value, callback)
 
 
-def traverse(d, callback):
+def traverse(d, callback) -> None:
     if not callable(callback):
         raise ValueError("callback argument must be a callable.")
     _traverse_collection(d, callback)
diff --git a/benedict/core/unflatten.py b/benedict/core/unflatten.py
index 23002e12..53fbf8bd 100644
--- a/benedict/core/unflatten.py
+++ b/benedict/core/unflatten.py
@@ -1,4 +1,4 @@
-from benedict.core import clone
+from benedict.core.clone import clone
 from benedict.dicts.keylist import keylist_util
 from benedict.utils import type_util
 
@@ -10,7 +10,7 @@ def _unflatten_item(key, value, separator):
     return (keys, value)
 
 
-def unflatten(d, separator="_"):
+def unflatten(d, separator: str = "_"):
     new_dict = clone(d, empty=True)
     keys = list(d.keys())
     for key in keys:
diff --git a/benedict/core/unique.py b/benedict/core/unique.py
index bd22e6bc..d26ea253 100644
--- a/benedict/core/unique.py
+++ b/benedict/core/unique.py
@@ -1,4 +1,4 @@
-def unique(d):
+def unique(d) -> None:
     values = []
     keys = list(d.keys())
     for key in keys:
diff --git a/benedict/dicts/__init__.py b/benedict/dicts/__init__.py
index 8fefd3c8..84bd787c 100644
--- a/benedict/dicts/__init__.py
+++ b/benedict/dicts/__init__.py
@@ -1,5 +1,6 @@
 # fix benedict json dumps support - #57 #59 #61
 from json import encoder
+from typing import Any
 
 # fix benedict yaml representer - #43
 from yaml import SafeDumper
@@ -38,7 +39,7 @@
 
 
 class benedict(KeypathDict, IODict, ParseDict):
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args, **kwargs: Any):
         """
         Constructs a new instance.
         """
@@ -188,7 +189,7 @@ def match(self, pattern, indexes=True):
         """
         return _match(self, pattern, separator=self._keypath_separator, indexes=indexes)
 
-    def merge(self, other, *args, **kwargs):
+    def merge(self, other, *args, **kwargs: Any):
         """
         Merge one or more dict objects into current instance (deepupdate).
         Sub-dictionaries will be merged toghether.
@@ -282,7 +283,7 @@ def unique(self):
 
 
 # fix benedict json dumps support - #57 #59 #61
-encoder.c_make_encoder = None
+encoder.c_make_encoder = None  # type: ignore
 
 # fix benedict yaml representer - #43
-SafeDumper.yaml_representers[benedict] = SafeRepresenter.represent_dict
+SafeDumper.yaml_representers[benedict] = SafeRepresenter.represent_dict  # type: ignore
diff --git a/benedict/dicts/base/base_dict.py b/benedict/dicts/base/base_dict.py
index 2a85c2d0..78731134 100644
--- a/benedict/dicts/base/base_dict.py
+++ b/benedict/dicts/base/base_dict.py
@@ -1,3 +1,5 @@
+from typing import Any
+
 from benedict.core import clone as _clone
 
 
@@ -17,7 +19,7 @@ def _get_dict_or_value(cls, value):
                     value[key] = key_val
         return value
 
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args, **kwargs: Any):
         if len(args) == 1 and isinstance(args[0], dict):
             self._dict = self._get_dict_or_value(args[0])
             self._pointer = True
@@ -134,7 +136,7 @@ def setdefault(self, key, default=None):
             return self._dict.setdefault(key, default)
         return super().setdefault(key, default)
 
-    def update(self, other):
+    def update(self, other):  # type: ignore # TODO: remove this ignore
         other = self._get_dict_or_value(other)
         if self._pointer:
             self._dict.update(other)
diff --git a/benedict/dicts/io/io_dict.py b/benedict/dicts/io/io_dict.py
index 77aa8c75..f8b2c4aa 100644
--- a/benedict/dicts/io/io_dict.py
+++ b/benedict/dicts/io/io_dict.py
@@ -1,10 +1,12 @@
+from typing import Any
+
 from benedict.dicts.base import BaseDict
 from benedict.dicts.io import io_util
 from benedict.utils import type_util
 
 
 class IODict(BaseDict):
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args, **kwargs: Any):
         """
         Constructs a new instance.
         """
@@ -19,7 +21,7 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
 
     @staticmethod
-    def _decode_init(s, **kwargs):
+    def _decode_init(s, **kwargs: Any):
         autodetected_format = io_util.autodetect_format(s)
         default_format = autodetected_format or "json"
         format = kwargs.pop("format", default_format).lower()
@@ -27,7 +29,7 @@ def _decode_init(s, **kwargs):
         return IODict._decode(s, format, **kwargs)
 
     @staticmethod
-    def _decode(s, format, **kwargs):
+    def _decode(s, format, **kwargs: Any):
         data = None
         try:
             data = io_util.decode(s, format, **kwargs)
@@ -43,12 +45,12 @@ def _decode(s, format, **kwargs):
             raise ValueError(f"Invalid data type: {type(data)}, expected dict or list.")
 
     @staticmethod
-    def _encode(d, format, **kwargs):
+    def _encode(d, format, **kwargs: Any) -> str:
         s = io_util.encode(d, format, **kwargs)
         return s
 
     @classmethod
-    def from_base64(cls, s, subformat="json", encoding="utf-8", **kwargs):
+    def from_base64(cls, s: str, subformat="json", encoding="utf-8", **kwargs: Any):
         """
         Load and decode Base64 data from url, filepath or data-string.
         Data is decoded according to subformat and encoding.
@@ -60,7 +62,7 @@ def from_base64(cls, s, subformat="json", encoding="utf-8", **kwargs):
         return cls(s, format="base64", **kwargs)
 
     @classmethod
-    def from_csv(cls, s, columns=None, columns_row=True, **kwargs):
+    def from_csv(cls, s: str, columns=None, columns_row=True, **kwargs: Any):
         """
         Load and decode CSV data from url, filepath or data-string.
         Decoder specific options can be passed using kwargs:
@@ -72,7 +74,7 @@ def from_csv(cls, s, columns=None, columns_row=True, **kwargs):
         return cls(s, format="csv", **kwargs)
 
     @classmethod
-    def from_ini(cls, s, **kwargs):
+    def from_ini(cls, s: str, **kwargs: Any):
         """
         Load and decode INI data from url, filepath or data-string.
         Decoder specific options can be passed using kwargs:
@@ -82,7 +84,7 @@ def from_ini(cls, s, **kwargs):
         return cls(s, format="ini", **kwargs)
 
     @classmethod
-    def from_json(cls, s, **kwargs):
+    def from_json(cls, s: str, **kwargs: Any):
         """
         Load and decode JSON data from url, filepath or data-string.
         Decoder specific options can be passed using kwargs:
@@ -92,7 +94,7 @@ def from_json(cls, s, **kwargs):
         return cls(s, format="json", **kwargs)
 
     @classmethod
-    def from_pickle(cls, s, **kwargs):
+    def from_pickle(cls, s: str, **kwargs: Any):
         """
         Load and decode a pickle encoded in Base64 format data from url, filepath or data-string.
         Decoder specific options can be passed using kwargs:
@@ -102,7 +104,7 @@ def from_pickle(cls, s, **kwargs):
         return cls(s, format="pickle", **kwargs)
 
     @classmethod
-    def from_plist(cls, s, **kwargs):
+    def from_plist(cls, s: str, **kwargs: Any):
         """
         Load and decode p-list data from url, filepath or data-string.
         Decoder specific options can be passed using kwargs:
@@ -112,7 +114,7 @@ def from_plist(cls, s, **kwargs):
         return cls(s, format="plist", **kwargs)
 
     @classmethod
-    def from_query_string(cls, s, **kwargs):
+    def from_query_string(cls, s: str, **kwargs: Any):
         """
         Load and decode query-string from url, filepath or data-string.
         Return a new dict instance. A ValueError is raised in case of failure.
@@ -120,7 +122,7 @@ def from_query_string(cls, s, **kwargs):
         return cls(s, format="query_string", **kwargs)
 
     @classmethod
-    def from_toml(cls, s, **kwargs):
+    def from_toml(cls, s: str, **kwargs: Any):
         """
         Load and decode TOML data from url, filepath or data-string.
         Decoder specific options can be passed using kwargs:
@@ -130,7 +132,7 @@ def from_toml(cls, s, **kwargs):
         return cls(s, format="toml", **kwargs)
 
     @classmethod
-    def from_xls(cls, s, sheet=0, columns=None, columns_row=True, **kwargs):
+    def from_xls(cls, s: str, sheet=0, columns=None, columns_row=True, **kwargs: Any):
         """
         Load and decode XLS files (".xls", ".xlsx", ".xlsm") from url, filepath or data-string.
         Decoder specific options can be passed using kwargs:
@@ -144,7 +146,7 @@ def from_xls(cls, s, sheet=0, columns=None, columns_row=True, **kwargs):
         return cls(s, format="xls", **kwargs)
 
     @classmethod
-    def from_xml(cls, s, **kwargs):
+    def from_xml(cls, s: str, **kwargs: Any):
         """
         Load and decode XML data from url, filepath or data-string.
         Decoder specific options can be passed using kwargs:
@@ -154,7 +156,7 @@ def from_xml(cls, s, **kwargs):
         return cls(s, format="xml", **kwargs)
 
     @classmethod
-    def from_yaml(cls, s, **kwargs):
+    def from_yaml(cls, s: str, **kwargs: Any):
         """
         Load and decode YAML data from url, filepath or data-string.
         Decoder specific options can be passed using kwargs:
@@ -163,7 +165,7 @@ def from_yaml(cls, s, **kwargs):
         """
         return cls(s, format="yaml", **kwargs)
 
-    def to_base64(self, subformat="json", encoding="utf-8", **kwargs):
+    def to_base64(self, subformat="json", encoding="utf-8", **kwargs: Any):
         """
         Encode the current dict instance in Base64 format
         using the given subformat and encoding.
@@ -175,7 +177,7 @@ def to_base64(self, subformat="json", encoding="utf-8", **kwargs):
         kwargs["encoding"] = encoding
         return self._encode(self.dict(), "base64", **kwargs)
 
-    def to_csv(self, key="values", columns=None, columns_row=True, **kwargs):
+    def to_csv(self, key="values", columns=None, columns_row=True, **kwargs: Any):
         """
         Encode a list of dicts in the current dict instance in CSV format.
         Encoder specific options can be passed using kwargs:
@@ -187,7 +189,7 @@ def to_csv(self, key="values", columns=None, columns_row=True, **kwargs):
         kwargs["columns_row"] = columns_row
         return self._encode(self.dict()[key], "csv", **kwargs)
 
-    def to_ini(self, **kwargs):
+    def to_ini(self, **kwargs: Any):
         """
         Encode the current dict instance in INI format.
         Encoder specific options can be passed using kwargs:
@@ -197,7 +199,7 @@ def to_ini(self, **kwargs):
         """
         return self._encode(self.dict(), "ini", **kwargs)
 
-    def to_json(self, **kwargs):
+    def to_json(self, **kwargs: Any):
         """
         Encode the current dict instance in JSON format.
         Encoder specific options can be passed using kwargs:
@@ -207,7 +209,7 @@ def to_json(self, **kwargs):
         """
         return self._encode(self.dict(), "json", **kwargs)
 
-    def to_pickle(self, **kwargs):
+    def to_pickle(self, **kwargs: Any):
         """
         Encode the current dict instance as pickle (encoded in Base64).
         The pickle protocol used by default is 2.
@@ -218,7 +220,7 @@ def to_pickle(self, **kwargs):
         """
         return self._encode(self.dict(), "pickle", **kwargs)
 
-    def to_plist(self, **kwargs):
+    def to_plist(self, **kwargs: Any):
         """
         Encode the current dict instance as p-list.
         Encoder specific options can be passed using kwargs:
@@ -228,7 +230,7 @@ def to_plist(self, **kwargs):
         """
         return self._encode(self.dict(), "plist", **kwargs)
 
-    def to_query_string(self, **kwargs):
+    def to_query_string(self, **kwargs: Any):
         """
         Encode the current dict instance in query-string format.
         Return the encoded string and optionally save it at 'filepath'.
@@ -236,7 +238,7 @@ def to_query_string(self, **kwargs):
         """
         return self._encode(self.dict(), "query_string", **kwargs)
 
-    def to_toml(self, **kwargs):
+    def to_toml(self, **kwargs: Any):
         """
         Encode the current dict instance in TOML format.
         Encoder specific options can be passed using kwargs:
@@ -246,7 +248,7 @@ def to_toml(self, **kwargs):
         """
         return self._encode(self.dict(), "toml", **kwargs)
 
-    def to_xml(self, **kwargs):
+    def to_xml(self, **kwargs: Any):
         """
         Encode the current dict instance in XML format.
         Encoder specific options can be passed using kwargs:
@@ -280,7 +282,7 @@ def to_xls(
         # return self._encode(self.dict()[key], "xls", **kwargs)
         raise NotImplementedError
 
-    def to_yaml(self, **kwargs):
+    def to_yaml(self, **kwargs: Any):
         """
         Encode the current dict instance in YAML format.
         Encoder specific options can be passed using kwargs:
diff --git a/benedict/dicts/io/io_util.py b/benedict/dicts/io/io_util.py
index 61ca645d..f8dae7f0 100644
--- a/benedict/dicts/io/io_util.py
+++ b/benedict/dicts/io/io_util.py
@@ -1,4 +1,5 @@
 import tempfile
+from typing import Any, Dict, Optional
 
 # from botocore.exceptions import ClientError
 from urllib.parse import urlparse
@@ -16,7 +17,7 @@ def autodetect_format(s):
     return None
 
 
-def decode(s, format, **kwargs):
+def decode(s: str, format: str, **kwargs: Any) -> Any:
     s = str(s)
     serializer = get_serializer_by_format(format)
     if not serializer:
@@ -29,7 +30,7 @@ def decode(s, format, **kwargs):
     return data
 
 
-def encode(d, format, filepath=None, **kwargs):
+def encode(d, format: str, filepath: Optional[str] = None, **kwargs: Any) -> str:
     serializer = get_serializer_by_format(format)
     if not serializer:
         raise ValueError(f"Invalid format: {format}.")
@@ -41,7 +42,7 @@ def encode(d, format, filepath=None, **kwargs):
     return content
 
 
-def is_binary_format(format):
+def is_binary_format(format: Optional[str]) -> bool:
     return format in [
         "xls",
         "xlsx",
@@ -49,23 +50,23 @@ def is_binary_format(format):
     ]
 
 
-def is_data(s):
+def is_data(s: str) -> bool:
     return len(s.splitlines()) > 1
 
 
-def is_filepath(s):
+def is_filepath(s: str) -> bool:
     return fsutil.is_file(s) or get_format_by_path(s)
 
 
-def is_s3(s):
+def is_s3(s: str) -> bool:
     return s.startswith("s3://") and get_format_by_path(s)
 
 
-def is_url(s):
+def is_url(s: str) -> bool:
     return any([s.startswith(protocol) for protocol in ["http://", "https://"]])
 
 
-def parse_s3_url(url):
+def parse_s3_url(url: str) -> Dict[str, str]:
     parsed = urlparse(url, allow_fragments=False)
     bucket = parsed.netloc
     key = parsed.path.lstrip("/")
@@ -79,7 +80,9 @@ def parse_s3_url(url):
     }
 
 
-def read_content(s, format=None, options=None):
+def read_content(
+    s: str, format: Optional[str] = None, options: Optional[Dict[str, Any]] = None
+) -> str:
     # s -> filepath or url or data
     # options.setdefault("format", format)
     options = options or {}
@@ -98,14 +101,16 @@ def read_content(s, format=None, options=None):
     return s
 
 
-def read_content_from_file(filepath, format=None):
+def read_content_from_file(filepath: str, format: Optional[str] = None) -> str:
     binary_format = is_binary_format(format)
     if binary_format:
         return filepath
     return fsutil.read_file(filepath)
 
 
-def read_content_from_s3(url, s3_options, format=None):
+def read_content_from_s3(
+    url: str, s3_options=Dict[str, Any], format: Optional[str] = None
+) -> str:
     s3_url = parse_s3_url(url)
     dirpath = tempfile.gettempdir()
     filename = fsutil.get_filename(s3_url["key"])
@@ -117,7 +122,9 @@ def read_content_from_s3(url, s3_options, format=None):
     return content
 
 
-def read_content_from_url(url, requests_options, format=None):
+def read_content_from_url(
+    url: str, requests_options: Dict[str, Any], format: Optional[str] = None
+) -> str:
     binary_format = is_binary_format(format)
     if binary_format:
         dirpath = tempfile.gettempdir()
@@ -126,18 +133,18 @@ def read_content_from_url(url, requests_options, format=None):
     return fsutil.read_file_from_url(url, **requests_options)
 
 
-def write_content(filepath, content, **options):
+def write_content(filepath: str, content: str, **options: Any) -> None:
     if is_s3(filepath):
         write_content_to_s3(filepath, content, **options)
     else:
         write_content_to_file(filepath, content, **options)
 
 
-def write_content_to_file(filepath, content, **options):
+def write_content_to_file(filepath: str, content: str, **options: Any) -> None:
     fsutil.write_file(filepath, content)
 
 
-def write_content_to_s3(url, content, s3_options, **options):
+def write_content_to_s3(url: str, content: str, s3_options, **options: Any) -> None:
     s3_url = parse_s3_url(url)
     dirpath = tempfile.gettempdir()
     filename = fsutil.get_filename(s3_url["key"])
diff --git a/benedict/dicts/keylist/keylist_dict.py b/benedict/dicts/keylist/keylist_dict.py
index 2f82dcea..98735b9b 100644
--- a/benedict/dicts/keylist/keylist_dict.py
+++ b/benedict/dicts/keylist/keylist_dict.py
@@ -1,30 +1,32 @@
+from typing import Any
+
 from benedict.dicts.base import BaseDict
 from benedict.dicts.keylist import keylist_util
 from benedict.utils import type_util
 
 
 class KeylistDict(BaseDict):
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args, **kwargs: Any):
         super().__init__(*args, **kwargs)
 
-    def __contains__(self, key):
+    def __contains__(self, key) -> bool:
         if type_util.is_list_or_tuple(key):
             return self._contains_by_keys(key)
         return super().__contains__(key)
 
-    def _contains_by_keys(self, keys):
+    def _contains_by_keys(self, keys) -> bool:
         parent, _, _ = keylist_util.get_item(self, keys)
         if type_util.is_dict_or_list_or_tuple(parent):
             return True
         return False
 
-    def __delitem__(self, key):
+    def __delitem__(self, key) -> None:
         if type_util.is_list_or_tuple(key):
             self._delitem_by_keys(key)
             return
         super().__delitem__(key)
 
-    def _delitem_by_keys(self, keys):
+    def _delitem_by_keys(self, keys) -> None:
         parent, key, _ = keylist_util.get_item(self, keys)
         if type_util.is_dict_or_list(parent):
             del parent[key]
@@ -85,7 +87,7 @@ def _pop_by_keys(self, keys, *args):
             return args[0]
         raise KeyError(f"Invalid keys: '{keys}'")
 
-    def set(self, key, value):
+    def set(self, key, value) -> None:
         self[key] = value
 
     def setdefault(self, key, default=None):
diff --git a/benedict/dicts/keypath/keypath_dict.py b/benedict/dicts/keypath/keypath_dict.py
index 7425f36f..990b0762 100644
--- a/benedict/dicts/keypath/keypath_dict.py
+++ b/benedict/dicts/keypath/keypath_dict.py
@@ -1,3 +1,5 @@
+from typing import Any, Optional
+
 from benedict.dicts import KeylistDict
 from benedict.dicts.keypath import keypath_util
 
@@ -6,7 +8,7 @@ class KeypathDict(KeylistDict):
 
     _keypath_separator = None
 
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args, **kwargs: Any):
         self._keypath_separator = kwargs.pop("keypath_separator", ".")
         check_keys = kwargs.pop("check_keys", True)
         super().__init__(*args, **kwargs)
@@ -14,24 +16,24 @@ def __init__(self, *args, **kwargs):
             keypath_util.check_keys(self, self._keypath_separator)
 
     @property
-    def keypath_separator(self):
+    def keypath_separator(self) -> Optional[str]:
         return self._keypath_separator
 
     @keypath_separator.setter
-    def keypath_separator(self, value):
+    def keypath_separator(self, value: str) -> None:
         keypath_util.check_keys(self, value)
         self._keypath_separator = value
 
-    def __contains__(self, key):
+    def __contains__(self, key) -> bool:
         return super().__contains__(self._parse_key(key))
 
-    def __delitem__(self, key):
+    def __delitem__(self, key) -> None:
         super().__delitem__(self._parse_key(key))
 
     def __getitem__(self, key):
         return super().__getitem__(self._parse_key(key))
 
-    def __setitem__(self, key, value):
+    def __setitem__(self, key, value) -> None:
         keypath_util.check_keys(value, self._keypath_separator)
         super().__setitem__(self._parse_key(key), value)
 
@@ -57,6 +59,6 @@ def get(self, key, default=None):
     def pop(self, key, *args):
         return super().pop(self._parse_key(key), *args)
 
-    def update(self, other):
+    def update(self, other) -> None:  # type: ignore # TODO: remove this ignore
         keypath_util.check_keys(other, self._keypath_separator)
         super().update(other)
diff --git a/benedict/dicts/parse/parse_dict.py b/benedict/dicts/parse/parse_dict.py
index ef421bd9..d45607b8 100644
--- a/benedict/dicts/parse/parse_dict.py
+++ b/benedict/dicts/parse/parse_dict.py
@@ -1,4 +1,5 @@
 from decimal import Decimal
+from typing import Any
 
 from benedict.dicts.base import BaseDict
 from benedict.dicts.parse import parse_util
@@ -6,7 +7,7 @@
 
 
 class ParseDict(BaseDict):
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args, **kwargs: Any):
         """
         Constructs a new instance.
         """
@@ -52,7 +53,7 @@ def _get_values_list(
         values_list = self.get_list(key, [], separator)
         return [parser_func(value, **(parser_kwargs or {})) for value in values_list]
 
-    def get_bool(self, key, default=False):
+    def get_bool(self, key, default: bool = False) -> bool:
         """
         Get value by key or keypath trying to return it as bool.
         Values like `1`, `true`, `yes`, `on` will be returned as `True`.
@@ -76,7 +77,7 @@ def get_date(self, key, default=None, format=None, choices=None):
             key, default, choices, parse_util.parse_date, {"format": format}
         )
 
-    def get_date_list(self, key, default=None, format=None, separator=","):
+    def get_date_list(self, key, default=None, format=None, separator: str = ","):
         """
         Get value by key or keypath trying to return it as list of date values.
         If separator is specified and value is a string it will be splitted.
@@ -95,7 +96,7 @@ def get_datetime(self, key, default=None, format=None, choices=None):
             key, default, choices, parse_util.parse_datetime, {"format": format}
         )
 
-    def get_datetime_list(self, key, default=None, format=None, separator=","):
+    def get_datetime_list(self, key, default=None, format=None, separator: str = ","):
         """
         Get value by key or keypath trying to return it as list of datetime values.
         If separator is specified and value is a string it will be splitted.
@@ -111,7 +112,7 @@ def get_decimal(self, key, default=Decimal("0.0"), choices=None):
         """
         return self._get_value(key, default, choices, parse_util.parse_decimal)
 
-    def get_decimal_list(self, key, default=None, separator=","):
+    def get_decimal_list(self, key, default=None, separator: str = ","):
         """
         Get value by key or keypath trying to return it as list of Decimal values.
         If separator is specified and value is a string it will be splitted.
@@ -146,7 +147,7 @@ def get_float(self, key, default=0.0, choices=None):
         """
         return self._get_value(key, default, choices, parse_util.parse_float)
 
-    def get_float_list(self, key, default=None, separator=","):
+    def get_float_list(self, key, default=None, separator: str = ","):
         """
         Get value by key or keypath trying to return it as list of float values.
         If separator is specified and value is a string it will be splitted.
@@ -176,7 +177,7 @@ def get_list(self, key, default=None, separator=","):
             key, default or [], None, parse_util.parse_list, {"separator": separator}
         )
 
-    def get_list_item(self, key, index=0, default=None, separator=","):
+    def get_list_item(self, key, index: int = 0, default=None, separator: str = ","):
         """
         Get list by key or keypath and return value at the specified index.
         If separator is specified and list value is a string it will be splitted.
@@ -206,21 +207,21 @@ def get_phonenumber(self, key, country_code=None, default=None):
             {"country_code": country_code},
         )
 
-    def get_slug(self, key, default="", choices=None):
+    def get_slug(self, key, default: str = "", choices=None) -> str:
         """
         Get value by key or keypath trying to return it as slug.
         If choices and value is in choices return value otherwise default.
         """
         return self._get_value(key, default, choices, parse_util.parse_slug)
 
-    def get_slug_list(self, key, default=None, separator=","):
+    def get_slug_list(self, key, default=None, separator: str = ","):
         """
         Get value by key or keypath trying to return it as list of slug values.
         If separator is specified and value is a string it will be splitted.
         """
         return self._get_values_list(key, default, separator, parse_util.parse_slug)
 
-    def get_str(self, key, default="", choices=None):
+    def get_str(self, key, default: str = "", choices=None) -> str:
         """
         Get value by key or keypath trying to return it as string.
         Encoding issues will be automatically fixed.
@@ -228,21 +229,21 @@ def get_str(self, key, default="", choices=None):
         """
         return self._get_value(key, default, choices, parse_util.parse_str)
 
-    def get_str_list(self, key, default=None, separator=","):
+    def get_str_list(self, key, default=None, separator: str = ","):
         """
         Get value by key or keypath trying to return it as list of str values.
         If separator is specified and value is a string it will be splitted.
         """
         return self._get_values_list(key, default, separator, parse_util.parse_str)
 
-    def get_uuid(self, key, default="", choices=None):
+    def get_uuid(self, key, default: str = "", choices=None) -> str:
         """
         Get value by key or keypath trying to return it as valid uuid.
         If choices and value is in choices return value otherwise default.
         """
         return self._get_value(key, default, choices, parse_util.parse_uuid)
 
-    def get_uuid_list(self, key, default=None, separator=","):
+    def get_uuid_list(self, key, default=None, separator: str = ","):
         """
         Get value by key or keypath trying to return it as list of valid uuid values.
         If separator is specified and value is a string it will be splitted.
diff --git a/benedict/dicts/parse/parse_util.py b/benedict/dicts/parse/parse_util.py
index 71460690..91bb66b1 100644
--- a/benedict/dicts/parse/parse_util.py
+++ b/benedict/dicts/parse/parse_util.py
@@ -1,6 +1,7 @@
 import re
 from datetime import datetime
 from decimal import Decimal, DecimalException
+from typing import Any
 
 import ftfy
 import phonenumbers
@@ -13,7 +14,7 @@
 from benedict.utils import type_util
 
 
-def _parse_with(val, type_checker, parser, **kwargs):
+def _parse_with(val, type_checker, parser, **kwargs: Any):
     if val is None:
         return None
     if callable(type_checker) and type_checker(val):
@@ -44,7 +45,7 @@ def parse_date(val, format=None):
     return None
 
 
-def _parse_datetime_with_format(val, format):
+def _parse_datetime_with_format(val, format: str):
     try:
         return datetime.strptime(val, format)
     except Exception:
diff --git a/benedict/py.typed b/benedict/py.typed
new file mode 100644
index 00000000..e69de29b
diff --git a/benedict/serializers/__init__.py b/benedict/serializers/__init__.py
index 48a35fed..b51da027 100644
--- a/benedict/serializers/__init__.py
+++ b/benedict/serializers/__init__.py
@@ -73,7 +73,7 @@ def get_format_by_path(path):
     return None
 
 
-def get_serializer_by_format(format):
+def get_serializer_by_format(format: str):
     format_key = (format or "").lower().strip()
     format_key = re.sub(r"[\s\-\_]*", "", format_key)
     serializer = _SERIALIZERS_BY_EXTENSION.get(format_key, None)
diff --git a/benedict/serializers/abstract.py b/benedict/serializers/abstract.py
index 67137b65..5fbfef07 100644
--- a/benedict/serializers/abstract.py
+++ b/benedict/serializers/abstract.py
@@ -1,17 +1,20 @@
+from typing import Any, List, Optional
+
+
 class AbstractSerializer:
     """
     This class describes an abstract serializer.
     """
 
-    def __init__(self, extensions=None):
+    def __init__(self, extensions: Optional[List[str]] = None):
         super().__init__()
         self._extensions = (extensions or []).copy()
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         raise NotImplementedError()
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         raise NotImplementedError()
 
-    def extensions(self):
+    def extensions(self) -> List[str]:
         return self._extensions.copy()
diff --git a/benedict/serializers/base64.py b/benedict/serializers/base64.py
index bf872e83..048ea11c 100644
--- a/benedict/serializers/base64.py
+++ b/benedict/serializers/base64.py
@@ -1,4 +1,5 @@
 import base64
+from typing import Any
 from urllib.parse import unquote
 
 from benedict.serializers.abstract import AbstractSerializer
@@ -18,7 +19,7 @@ def __init__(self):
             ],
         )
 
-    def _fix_url_encoding_and_padding(self, s):
+    def _fix_url_encoding_and_padding(self, s: str) -> str:
         # fix urlencoded chars
         s = unquote(s)
         # fix padding
@@ -27,17 +28,17 @@ def _fix_url_encoding_and_padding(self, s):
             s += "=" * (4 - m)
         return s
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         value = self._fix_url_encoding_and_padding(s)
         encoding = kwargs.pop("encoding", "utf-8")
-        if encoding:
-            value = value.encode(encoding)
-        value = base64.b64decode(value)
-        if encoding:
-            return value.decode(encoding)
+        # if encoding:
+        #    value = value.encode(encoding)
+        value = base64.b64decode(value).decode(encoding)
+        # if encoding:
+        #     return value.decode(encoding)
         return value
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         value = d
         encoding = kwargs.pop("encoding", "utf-8")
         if encoding and type_util.is_string(value):
@@ -60,14 +61,14 @@ def _pop_options(self, options):
         serializer = get_serializer_by_format(subformat)
         return (serializer, encoding)
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         serializer, encoding = self._pop_options(kwargs)
         value = super().decode(s, encoding=encoding)
         if serializer:
             value = serializer.decode(value, **kwargs)
         return value
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         serializer, encoding = self._pop_options(kwargs)
         value = d
         if serializer:
diff --git a/benedict/serializers/csv.py b/benedict/serializers/csv.py
index 97ea5481..10a41e2b 100644
--- a/benedict/serializers/csv.py
+++ b/benedict/serializers/csv.py
@@ -1,5 +1,6 @@
 import csv
 from io import StringIO
+from typing import Any
 
 from benedict.serializers.abstract import AbstractSerializer
 from benedict.utils import type_util
@@ -17,7 +18,7 @@ def __init__(self):
             ],
         )
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         # kwargs.setdefault('delimiter', ',')
         if kwargs.pop("quote", False):
             # TODO: add tests coverage
@@ -39,7 +40,7 @@ def decode(self, s, **kwargs):
             ln += 1
         return data
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         ls = d
         # kwargs.setdefault('delimiter', ',')
         if kwargs.pop("quote", False):
diff --git a/benedict/serializers/ini.py b/benedict/serializers/ini.py
index 09e2f1d7..608b2617 100644
--- a/benedict/serializers/ini.py
+++ b/benedict/serializers/ini.py
@@ -1,6 +1,7 @@
 from configparser import DEFAULTSECT as default_section
 from configparser import ConfigParser
 from io import StringIO
+from typing import Any
 
 from benedict.serializers.abstract import AbstractSerializer
 from benedict.utils import type_util
@@ -30,7 +31,7 @@ def _get_section_option_value(parser, section, option):
                 continue
         return value
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         parser = ConfigParser(**kwargs)
         parser.read_string(s)
         data = {}
@@ -46,7 +47,7 @@ def decode(self, s, **kwargs):
                 )
         return data
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         parser = ConfigParser(**kwargs)
         for key, value in d.items():
             if not type_util.is_dict(value):
diff --git a/benedict/serializers/json.py b/benedict/serializers/json.py
index 89b9af6b..d703624f 100644
--- a/benedict/serializers/json.py
+++ b/benedict/serializers/json.py
@@ -1,4 +1,5 @@
 import json
+from typing import Any
 
 from benedict.serializers.abstract import AbstractSerializer
 from benedict.utils import type_util
@@ -16,11 +17,11 @@ def __init__(self):
             ],
         )
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         data = json.loads(s, **kwargs)
         return data
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         kwargs.setdefault("default", self._encode_default)
         data = json.dumps(d, **kwargs)
         return data
diff --git a/benedict/serializers/pickle.py b/benedict/serializers/pickle.py
index 20680139..76fee208 100644
--- a/benedict/serializers/pickle.py
+++ b/benedict/serializers/pickle.py
@@ -1,5 +1,6 @@
 import base64
 import pickle
+from typing import Any
 
 from benedict.serializers.abstract import AbstractSerializer
 
@@ -16,11 +17,11 @@ def __init__(self):
             ],
         )
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         encoding = kwargs.pop("encoding", "utf-8")
         return pickle.loads(base64.b64decode(s.encode(encoding)), **kwargs)
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         encoding = kwargs.pop("encoding", "utf-8")
         kwargs.setdefault("protocol", 2)
         return base64.b64encode(pickle.dumps(d, **kwargs)).decode(encoding)
diff --git a/benedict/serializers/plist.py b/benedict/serializers/plist.py
index 10619b24..77a1291c 100644
--- a/benedict/serializers/plist.py
+++ b/benedict/serializers/plist.py
@@ -1,4 +1,5 @@
 import plistlib
+from typing import Any
 
 from benedict.serializers.abstract import AbstractSerializer
 
@@ -16,11 +17,11 @@ def __init__(self):
             ],
         )
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         kwargs.setdefault("fmt", plistlib.FMT_XML)
         encoding = kwargs.pop("encoding", "utf-8")
         return plistlib.loads(s.encode(encoding), **kwargs)
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         encoding = kwargs.pop("encoding", "utf-8")
         return plistlib.dumps(d, **kwargs).decode(encoding)
diff --git a/benedict/serializers/query_string.py b/benedict/serializers/query_string.py
index 1816379b..29c9959d 100644
--- a/benedict/serializers/query_string.py
+++ b/benedict/serializers/query_string.py
@@ -1,4 +1,5 @@
 import re
+from typing import Any
 from urllib.parse import parse_qs, urlencode
 
 from benedict.serializers.abstract import AbstractSerializer
@@ -17,17 +18,17 @@ def __init__(self):
             ],
         )
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         flat = kwargs.pop("flat", True)
         qs_re = r"(?:([\w\-\%\+\.\|]+\=[\w\-\%\+\.\|]*)+(?:[\&]{1})?)+"
         qs_pattern = re.compile(qs_re)
         if qs_pattern.match(s):
-            data = parse_qs(s)
+            qs_data = parse_qs(s)
             if flat:
-                data = {key: value[0] for key, value in data.items()}
+                data = {key: value[0] for key, value in qs_data.items()}
             return data
         raise ValueError(f"Invalid query string: {s}")
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         data = urlencode(d, **kwargs)
         return data
diff --git a/benedict/serializers/toml.py b/benedict/serializers/toml.py
index 304aadaf..172827e3 100644
--- a/benedict/serializers/toml.py
+++ b/benedict/serializers/toml.py
@@ -1,3 +1,5 @@
+from typing import Any
+
 import toml
 
 try:
@@ -23,13 +25,13 @@ def __init__(self):
             ],
         )
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         if tomllib_available:
             data = tomllib.loads(s, **kwargs)
         else:
             data = toml.loads(s, **kwargs)
         return data
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         data = toml.dumps(dict(d), **kwargs)
         return data
diff --git a/benedict/serializers/xls.py b/benedict/serializers/xls.py
index e49d5673..dbffa650 100644
--- a/benedict/serializers/xls.py
+++ b/benedict/serializers/xls.py
@@ -1,3 +1,5 @@
+from typing import Any, List
+
 import fsutil
 from openpyxl import load_workbook
 from slugify import slugify
@@ -20,7 +22,7 @@ def __init__(self):
             ],
         )
 
-    def _get_sheet_index_and_name_from_options(self, **kwargs):
+    def _get_sheet_index_and_name_from_options(self, **kwargs: Any):
         sheet_index_or_name = kwargs.pop("sheet", 0)
         sheet_index = 0
         sheet_name = ""
@@ -30,7 +32,7 @@ def _get_sheet_index_and_name_from_options(self, **kwargs):
             sheet_name = sheet_index_or_name
         return (sheet_index, sheet_name)
 
-    def _get_sheet_index_by_name(self, sheet_name, sheet_names):
+    def _get_sheet_index_by_name(self, sheet_name: str, sheet_names: List[str]) -> int:
         sheet_names = list([slugify(name) for name in sheet_names])
         try:
             sheet_index = sheet_names.index(slugify(sheet_name))
@@ -38,10 +40,10 @@ def _get_sheet_index_by_name(self, sheet_name, sheet_names):
         except ValueError:
             raise Exception(f"Invalid sheet name '{sheet_name}', sheet not found.")
 
-    def _get_sheet_columns_indexes(self, columns_count):
+    def _get_sheet_columns_indexes(self, columns_count: int) -> List[int]:
         return [column_index for column_index in range(columns_count)]
 
-    def _decode_legacy(self, s, **kwargs):
+    def _decode_legacy(self, s: str, **kwargs: Any):
         filepath = s
 
         # load the worksheet
@@ -69,7 +71,7 @@ def _decode_legacy(self, s, **kwargs):
             else:
                 # otherwise use columns indexes as column names
                 # for row in sheet.iter_rows(min_row=1, max_row=1):
-                columns = self._get_sheet_columns_indexes(sheet_columns_range)
+                columns = self._get_sheet_columns_indexes(len(sheet_columns_range))
 
         # standardize column names, eg. "Date Created" -> "date_created"
         if columns_standardized:
@@ -89,7 +91,7 @@ def _decode_legacy(self, s, **kwargs):
         # print(items)
         return items
 
-    def _decode(self, s, **kwargs):
+    def _decode(self, s: str, **kwargs: Any):
         filepath = s
 
         # load the worksheet
@@ -135,12 +137,12 @@ def _decode(self, s, **kwargs):
         # print(items)
         return items
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         extension = fsutil.get_file_extension(s)
         if extension in ["xlsx", "xlsm"]:
             return self._decode(s, **kwargs)
         elif extension in ["xls", "xlt"]:
             return self._decode_legacy(s, **kwargs)
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         raise NotImplementedError
diff --git a/benedict/serializers/xml.py b/benedict/serializers/xml.py
index b6ce1c1a..d01d97f2 100644
--- a/benedict/serializers/xml.py
+++ b/benedict/serializers/xml.py
@@ -1,3 +1,5 @@
+from typing import Any
+
 import xmltodict
 
 from benedict.serializers.abstract import AbstractSerializer
@@ -15,11 +17,11 @@ def __init__(self):
             ],
         )
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         kwargs.setdefault("dict_constructor", dict)
         data = xmltodict.parse(s, **kwargs)
         return data
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any):
         data = xmltodict.unparse(d, **kwargs)
         return data
diff --git a/benedict/serializers/yaml.py b/benedict/serializers/yaml.py
index cdc61eda..75b5eeff 100644
--- a/benedict/serializers/yaml.py
+++ b/benedict/serializers/yaml.py
@@ -1,3 +1,5 @@
+from typing import Any
+
 import yaml
 
 from benedict.serializers.abstract import AbstractSerializer
@@ -18,11 +20,11 @@ def __init__(self):
         )
         self._json_serializer = JSONSerializer()
 
-    def decode(self, s, **kwargs):
+    def decode(self, s: str, **kwargs: Any):
         data = yaml.safe_load(s, **kwargs)
         return data
 
-    def encode(self, d, **kwargs):
+    def encode(self, d, **kwargs: Any) -> str:
         d = self._json_serializer.decode(self._json_serializer.encode(d))
         data = yaml.dump(d, **kwargs)
         return data
diff --git a/benedict/utils/type_util.py b/benedict/utils/type_util.py
index 476d66e5..abb00eaf 100644
--- a/benedict/utils/type_util.py
+++ b/benedict/utils/type_util.py
@@ -2,6 +2,7 @@
 import re
 from datetime import datetime
 from decimal import Decimal
+from typing import Any
 
 regex = re.compile("").__class__
 uuid_re = re.compile(
@@ -10,86 +11,86 @@
 )
 
 
-def is_bool(val):
+def is_bool(val: Any) -> bool:
     return isinstance(val, bool)
 
 
-def is_collection(val):
+def is_collection(val: Any) -> bool:
     return isinstance(val, (dict, list, set, tuple))
 
 
-def is_datetime(val):
+def is_datetime(val: Any) -> bool:
     return isinstance(val, datetime)
 
 
-def is_decimal(val):
+def is_decimal(val: Any) -> bool:
     return isinstance(val, Decimal)
 
 
-def is_dict(val):
+def is_dict(val: Any) -> bool:
     return isinstance(val, dict)
 
 
-def is_dict_or_list(val):
+def is_dict_or_list(val: Any) -> bool:
     return isinstance(val, (dict, list))
 
 
-def is_dict_or_list_or_tuple(val):
+def is_dict_or_list_or_tuple(val: Any) -> bool:
     return isinstance(val, (dict, list, tuple))
 
 
-def is_float(val):
+def is_float(val: Any) -> bool:
     return isinstance(val, float)
 
 
-def is_function(val):
+def is_function(val: Any) -> bool:
     return callable(val)
 
 
-def is_integer(val):
+def is_integer(val: Any) -> bool:
     return isinstance(val, int)
 
 
-def is_json_serializable(val):
+def is_json_serializable(val: Any) -> bool:
     json_types = (type(None), bool, dict, float, int, list, str, tuple)
     return isinstance(val, json_types)
 
 
-def is_list(val):
+def is_list(val: Any) -> bool:
     return isinstance(val, list)
 
 
-def is_list_or_tuple(val):
+def is_list_or_tuple(val: Any) -> bool:
     return isinstance(val, (list, tuple))
 
 
-def is_none(val):
+def is_none(val: Any) -> bool:
     return val is None
 
 
-def is_not_none(val):
+def is_not_none(val: Any) -> bool:
     return val is not None
 
 
-def is_path(val):
+def is_path(val: Any) -> bool:
     return isinstance(val, pathlib.Path)
 
 
-def is_regex(val):
+def is_regex(val: Any) -> bool:
     return isinstance(val, regex)
 
 
-def is_set(val):
+def is_set(val: Any) -> bool:
     return isinstance(val, set)
 
 
-def is_string(val):
+def is_string(val: Any) -> bool:
     return isinstance(val, str)
 
 
-def is_tuple(val):
+def is_tuple(val: Any) -> bool:
     return isinstance(val, tuple)
 
 
-def is_uuid(val):
-    return is_string(val) and uuid_re.match(val)
+def is_uuid(val: Any) -> bool:
+    return is_string(val) and bool(uuid_re.match(val))

From 1550628290aa223c356a96913b2ec0dcb98fdbf4 Mon Sep 17 00:00:00 2001
From: Fabio Caccamo <fabio.caccamo@gmail.com>
Date: Thu, 9 Feb 2023 10:49:04 +0100
Subject: [PATCH 5/6] Fix too many positional arguments for `download_file`.

---
 benedict/dicts/io/io_util.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/benedict/dicts/io/io_util.py b/benedict/dicts/io/io_util.py
index f8dae7f0..d416b8c1 100644
--- a/benedict/dicts/io/io_util.py
+++ b/benedict/dicts/io/io_util.py
@@ -128,7 +128,7 @@ def read_content_from_url(
     binary_format = is_binary_format(format)
     if binary_format:
         dirpath = tempfile.gettempdir()
-        filepath = fsutil.download_file(url, dirpath, **requests_options)
+        filepath = fsutil.download_file(url, dirpath=dirpath, **requests_options)
         return filepath
     return fsutil.read_file_from_url(url, **requests_options)
 

From 2f65b9dba6d9d88b62d75e05dff8f26082466016 Mon Sep 17 00:00:00 2001
From: Fabio Caccamo <fabio.caccamo@gmail.com>
Date: Thu, 9 Feb 2023 11:54:12 +0100
Subject: [PATCH 6/6] Add `fix-future-annotations` `pre-commit` hook.

---
 .pre-commit-config.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 0acf44f1..156848ce 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -7,6 +7,11 @@ repos:
     hooks:
       - id: pyupgrade
 
+  - repo: https://github.com/frostming/fix-future-annotations
+    rev: 0.5.0
+    hooks:
+      - id: fix-future-annotations
+
   - repo: https://github.com/psf/black
     rev: 23.1.0
     hooks: