Accessor/Base.py: add exception for data type values

product/ERP5Type/Accessor/Base.py

@@ -92,7 +92,7 @@ class Setter(Method):
       # Modify the property
       if value in self._null:
         setattr(instance, self._storage_id, None)
-      elif not isinstance(value, builtin_type_tuple):
+      elif not isinstance(value, builtin_type_tuple) and self._property_type != 'data':
         raise TypeError('Class Objects can\'t be used as property values')
       elif self._property_type == 'content':
         # A file object should be provided