Python 3.6 compatibility regarding contextvars usage in progress bars.

jonathanslenders · jonathanslenders · commit f38ad93bcf56 · 2019-05-20T21:58:22.000+02:00
diff --git a/prompt_toolkit/shortcuts/progress_bar/base.py b/prompt_toolkit/shortcuts/progress_bar/base.py
@@ -8,7 +8,6 @@
             ...
 """
 import contextlib
-import contextvars
 import datetime
 import functools
 import os
@@ -63,6 +62,12 @@
 
 from .formatters import Formatter, create_default_formatters
 
+try:
+    import contextvars
+except ImportError:
+    from prompt_toolkit.eventloop import dummy_contextvars as contextvars
+
+
 __all__ = [
     'ProgressBar',
 ]
