public static function filter_array( $list, $args, $operator = 'AND' ) {
		if ( ! is_array($args) ) {
			$args = array( 'slug' => $args );
		}

		if ( ! is_array( $list ) && ! is_a( $list, 'Traversable' ) ) {
			return array();
		}

		$util = new \WP_List_Util( $list );
		return $util->filter( $args, $operator );
	}