protected function handle($item, callable $filter = null)
    {
        if (null !== $filter) {
            return call_user_func($filter, $item);
        }
        return $item;
    }
protected function handle($item, callable $filter = null)
    {
        if (null !== $filter) {
            return call_user_func($filter, $item);
        }
        return $item;
    }
protected function handle ( $ item , callable $ filter = null ) { if ( null !== $ filter ) { return call_user_func ( $ filter , $ item ) ; } return $ item ; }
Filter an item with a callback
@param  mixed         $item
@param  callable|null $filter
@return mixed
Filter an item with a callback