def add_message(self, message_type):
name = self.__normalized_name(message_type)<EOL>if name not in self.__schemas:<EOL><INDENT>self.__schemas[name] = None<EOL>schema = self.__message_to_schema(message_type)<EOL>self.__schemas[name] = schema<EOL><DEDENT>return name<EOL>
Add a new message.

        Args:
          message_type: protorpc.message.Message class to be parsed.

        Returns:
          string, The JSON Schema id.

        Raises:
          KeyError if the Schema id for this message_type would collide with the
          Schema id of a different message_type that was already added.