Get the type and check the identity with tuple, instead of using isinstance,...

Get the type and check the identity with tuple, instead of using isinstance, because isinstance is slower, when accessor is not of tuple, and there is no reason to check subclass instances here.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@18647 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/Base.py

@@ -846,7 +846,7 @@ class Base( CopyContainer,
     try:
       property_holder = Base.aq_portal_type[aq_key]
       accessor = getattr(property_holder, id, None)
-      if isinstance(accessor, tuple):
+      if type(accessor) is tuple:
         if id not in RESERVED_TUPLE_PROPERTY:
           property_holder.createAccessor(id)
           accessor = getattr(property_holder, id, None)