docs: def _init_metadata(self):
          """stub"""
          self._choice_ids_metadata = {
              'element_id': Id(self.my_osid_object_form._authority,
                               self.my_osid_object_form._namespace,
                               'choice_ids'),
              'element_label': 'response set',
              'instructions': 'submit correct choice for answer',
              'required': False,
              'read_only': False,
              'linked': False,
              'array': False,
              'default_object_values': [[]],
              'syntax': 'OBJECT',
          }
          self._choice_id_metadata = {
              'element_id': Id(self.my_osid_object_form._authority,
                               self.my_osid_object_form._namespace,
                               'choice_id'),
              'element_label': 'response set',
              'instructions': 'submit correct choice for answer',
              'required': True,
              'read_only': False,
              'linked': False,
              'array': False,
              'default_id_values': [''],
              'syntax': 'ID',
              'id_set': []
          }