public function filter(array $keys)
    {
        $this->parameters = array_intersect_key($this->parameters, array_flip($keys));

        return $this;
    }
public function filter(array $keys)
    {
        $this->parameters = array_intersect_key($this->parameters, array_flip($keys));

        return $this;
    }
public function filter ( array $ keys ) { $ this -> parameters = array_intersect_key ( $ this -> parameters , array_flip ( $ keys ) ) ; return $ this ; }
Filter current bag with specific parameters by keys.

@param array $keys

@return $this
Filter current bag with specific parameters by keys .