docs: def _init_metadata(self, **kwargs):
          """Initialize form metadata"""
  
          osid_objects.OsidContainableForm._init_metadata(self)
          osid_objects.OsidSourceableForm._init_metadata(self)
          osid_objects.OsidObjectForm._init_metadata(self, **kwargs)
          self._children_default = self._mdata['children']['default_id_values']