--- a/cwvreg.py	Thu Mar 26 18:54:55 2009 +0100
+++ b/cwvreg.py	Thu Mar 26 18:57:58 2009 +0100
@@ -121,12 +121,12 @@
             if not self.config.cleanup_interface_sobjects:
                 return
             # remove vobjects that don't support any available interface
-            interfaces = set()
+            implemented_interfaces = set()
             for classes in self.get('etypes', {}).values():
                 for cls in classes:
                     for iface in cls.__implements__:
-                        interfaces.update(iface.__mro__)
-                    interfaces.update(cls.__mro__)
+                        implemented_interfaces.update(iface.__mro__)
+                    implemented_interfaces.update(cls.__mro__)
             for obj, ifaces in self._needs_iface.items():
                 ifaces = frozenset(isinstance(iface, basestring)
                                    and iface in self.schema