abc's are subclasses of _Abstract, not instances.
diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
index 55817ff..0202207 100755
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -701,7 +701,7 @@
pic = sys.path_importer_cache.copy()
abcs = {obj: obj._abc_registry.copy()
for abc in [getattr(_abcoll, a) for a in _abcoll.__all__
- if isinstance(getattr(_abcoll, a), _Abstract)]
+ if issubclass(getattr(_abcoll, a), _Abstract)]
for obj in abc.__subclasses__() + [abc]}
if indirect_test:
@@ -751,7 +751,7 @@
# Clear ABC registries, restoring previously saved ABC registries.
for abc in [getattr(_abcoll, a) for a in _abcoll.__all__]:
- if not isinstance(abc, _Abstract):
+ if not issubclass(abc, _Abstract):
continue
for obj in abc.__subclasses__() + [abc]:
obj._abc_registry = abcs.get(obj, {}).copy()