- add a test for pullreq 8

- simplify

1 files changed, 3 insertions, 3 deletions

diff --git a/lib/sqlalchemy/ext/mutable.py b/lib/sqlalchemy/ext/mutable.py
index 48c8d13cc..d3133b1f5 100644
--- a/lib/sqlalchemy/ext/mutable.py
+++ b/lib/sqlalchemy/ext/mutable.py
@@ -588,11 +588,11 @@ class MutableComposite(MutableBase):
                 setattr(parent, attr_name, value)
 
 def _setup_composite_listener():
-    import types
     def _listen_for_type(mapper, class_):
         for prop in mapper.iterate_properties:
-            if (hasattr(prop, 'composite_class') and (type(prop.composite_class) in (types.ClassType, types.TypeType)) and
-                issubclass(prop.composite_class, MutableComposite)):
+            if (hasattr(prop, 'composite_class') and
+                isinstance(prop.composite_class, type) and
+                 issubclass(prop.composite_class, MutableComposite)):
                 prop.composite_class._listen_on_attribute(
                     getattr(class_, prop.key), False, class_)
     if not Mapper.dispatch.mapper_configured._contains(Mapper, _listen_for_type):