diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 8990602577bd..b73d7f7f48f4 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -885,7 +885,9 @@ def __str__(self):
 
     def __iter__(self):
         """Yield sorted list of keys."""
-        yield from sorted(dict.__iter__(self))
+        with warnings.catch_warnings():
+            warnings.simplefilter('ignore', MatplotlibDeprecationWarning)
+            yield from sorted(dict.__iter__(self))
 
     def __len__(self):
         return dict.__len__(self)
@@ -907,8 +909,7 @@ def find_all(self, pattern):
                         if pattern_re.search(key))
 
     def copy(self):
-        return {k: dict.__getitem__(self, k)
-                for k in self}
+        return {k: dict.__getitem__(self, k) for k in self}
 
 
 def rc_params(fail_on_error=False):