def meta_data_hash(self, obj_hash=None):
        """Creates a hash with the meta data of the model

        :param obj_hash: The hash object (see Python hashlib)
        :return: The updated hash object
        """
        if obj_hash is None:
            obj_hash = hashlib.sha256()
        self.update_meta_data_hash(obj_hash)
        return obj_hash