bpo-41515: Fix KeyError raised in get_type_hints (GH-25352)

Co-authored-by: Ken Jin <28750310+Fidget-Spinner@users.noreply.github.com>
Co-authored-by: efahl <36704995+efahl@users.noreply.github.com>
diff --git a/Lib/typing.py b/Lib/typing.py
index 583438e..dc2a7a4 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -1628,7 +1628,10 @@ def get_type_hints(obj, globalns=None, localns=None, include_extras=False):
         hints = {}
         for base in reversed(obj.__mro__):
             if globalns is None:
-                base_globals = sys.modules[base.__module__].__dict__
+                try:
+                    base_globals = sys.modules[base.__module__].__dict__
+                except KeyError:
+                    continue
             else:
                 base_globals = globalns
             ann = base.__dict__.get('__annotations__', {})