Bugfixe in leobject

Deleted hardcoded condition that brokes standart field validation process

lodel/leapi/datahandlers/base_classes.py

     # @param internal bool : if False, the field is not internal
     # @param **kwargs : other arguments
     def __init__(self, allowed_classes = None, back_reference = None, internal=False, **kwargs):
-        self.__allowed_classes = [] if allowed_classes is None else set(allowed_classes)
+        self.__allowed_classes = set() if allowed_classes is None else set(allowed_classes)
         logger.warning("We're going to inialize an temporary attribute, don't forget to fix this issue")
         if back_reference is not None:
             if len(back_reference) != 2:

lodel/leapi/leobject.py

         correct = set() #valid fields name
         mandatory = set() #mandatory fields name
         for fname, datahandler in cls._fields.items():
-            if allow_internal or not datahandler.is_internal() or fname == CLASS_ID_FIELDNAME:
+            if allow_internal or not datahandler.is_internal():
                 correct.add(fname)
                 if complete and not hasattr(datahandler, 'default'):
                     mandatory.add(fname)