protected function keys()
    {
        if (count($this->before()) > count($this->after())) {
            return $this->before();
        }

        return $this->after();
    }
protected function keys()
    {
        if (count($this->before()) > count($this->after())) {
            return $this->before();
        }

        return $this->after();
    }
protected function keys ( ) { if ( count ( $ this -> before ( ) ) > count ( $ this -> after ( ) ) ) { return $ this -> before ( ) ; } return $ this -> after ( ) ; }
Get diff keys.

@return array
Get diff keys .