Merged in bug fix # 1344 to PermissionMapping.

lib/python/AccessControl/PermissionMapping.py

@@ -165,7 +165,8 @@ class RoleManager:
     def _isBeingAccessedAsZClassDefinedInstanceMethod(self):
         p=getattr(self,'aq_parent',None)
         if p is None: return 0          # Not wrapped
-        return type(p.aq_base) is PermissionMapper  
+        base=getattr(p, 'aq_base', None)
+        return type(base) is PermissionMapper