Issue #11085: Moved collections abstract base classes into a separate module
called collections.abc, following the pattern used by importlib.abc. For
backwards compatibility, the names continue to also be imported into the
collections module.
diff --git a/Lib/os.py b/Lib/os.py
index 3ef3db8..9720479 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -434,7 +434,7 @@
# Change environ to automatically call putenv(), unsetenv if they exist.
-from _abcoll import MutableMapping # Can't use collections (bootstrap)
+from collections.abc import MutableMapping
class _Environ(MutableMapping):
def __init__(self, data, encodekey, decodekey, encodevalue, decodevalue, putenv, unsetenv):