code: def _GetAttributeNames(self, data_type_definition):
      
      if not data_type_definition:
        raise errors.FormatError('Missing data type definition')
  
      attribute_names = []
      for member_definition in data_type_definition.members:
        attribute_names.append(member_definition.name)
  
      return attribute_names
docs: Determines the attribute (or field) names of the members.
  
      Args:
        data_type_definition (DataTypeDefinition): data type definition.
  
      Returns:
        list[str]: attribute names.
  
      Raises:
        FormatError: if the attribute names cannot be determined from the data
            type definition.