public function list_( $args, $assoc_args ) {

		list( $sidebar_id ) = $args;

		$this->validate_sidebar( $sidebar_id );

		$output_widgets = $this->get_sidebar_widgets( $sidebar_id );

		if ( ! empty( $assoc_args['format'] ) && 'ids' === $assoc_args['format'] ) {
			$output_widgets = wp_list_pluck( $output_widgets, 'id' );
		}

		$formatter = new Formatter( $assoc_args, $this->fields );
		$formatter->display_items( $output_widgets );

	}