code: def _verified_content_type_from_id(content_type_id):
      # type: (int) -> ContentType
      
      try:
          return ContentType(content_type_id)
      except ValueError as error:
          raise UnknownIdentityError("Unknown content type {}".format(content_type_id), error)
docs: Load a message :class:`ContentType` for the specified content type ID.
  
      :param int content_type_id: Content type ID
      :return: Message content type
      :rtype: ContentType
      :raises UnknownIdentityError: if unknown content type ID is received