public function isEmpty($keys = null)
    {
        if (is_null($keys)) {
            return empty($this->elements);
        }
        $keys = (array) $keys;
        foreach ($keys as $key) {
            if (!empty($this->get($key))) {
                return false;
            }
        }
        return true;
    }
public function isEmpty($keys = null)
    {
        if (is_null($keys)) {
            return empty($this->elements);
        }
        $keys = (array) $keys;
        foreach ($keys as $key) {
            if (!empty($this->get($key))) {
                return false;
            }
        }
        return true;
    }
public function isEmpty ( $ keys = null ) { if ( is_null ( $ keys ) ) { return empty ( $ this -> elements ) ; } $ keys = ( array ) $ keys ; foreach ( $ keys as $ key ) { if ( ! empty ( $ this -> get ( $ key ) ) ) { return false ; } } return true ; }
Check if a given key or keys are empty

@param  array|int|string|null $keys
@return bool
Check if a given key or keys are empty