public function save_field( $post_id, $field, $old, $new ) {
		$name = $field['meta'];

		delete_post_meta( $post_id, $name );
		if ( $new === '' || $new === array() ) {
			return;
		}

		if ( $field['multiple'] ) {
			foreach ( $new as $add_new ) {
				add_post_meta( $post_id, $name, $add_new, false );
			}
		} else {
			update_post_meta( $post_id, $name, $new );
		}
	}