code: def register_add_user_command(self, add_user_func):
          
          description = "Gives user permission to access a remote project."
          add_user_parser = self.subparsers.add_parser('add-user', description=description)
          add_project_name_or_id_arg(add_user_parser, help_text_suffix="add a user to")
          user_or_email = add_user_parser.add_mutually_exclusive_group(required=True)
          add_user_arg(user_or_email)
          add_email_arg(user_or_email)
          _add_auth_role_arg(add_user_parser, default_permissions='project_admin')
          add_user_parser.set_defaults(func=add_user_func)
docs: Add the add-user command to the parser and call add_user_func(project_name, user_full_name, auth_role)
          when chosen.
          :param add_user_func: func Called when this option is chosen: upload_func(project_name, user_full_name, auth_role).