code: def register_sub_command(self, sub_command, additional_ids=[]):
          
          self.__register_sub_command(sub_command, sub_command.command_desc().command)
          self.__additional_ids.update(additional_ids)
          for id in additional_ids:
              self.__register_sub_command(sub_command, id)
docs: Register a command as a subcommand.
          It will have it's CommandDesc.command string used as id. Additional ids can be provided.
  
          Args:
              sub_command (CommandBase): Subcommand to register.
              additional_ids (List[str]): List of additional ids. Can be empty.