public function getValue($key)
    {
        if (!isset($this->values[$key])) {
            return null;
        }
        return $this->values[$key];
    }
public function getValue($key)
    {
        if (!isset($this->values[$key])) {
            return null;
        }
        return $this->values[$key];
    }
public function getValue ( $ key ) { if ( ! isset ( $ this -> values [ $ key ] ) ) { return null ; } return $ this -> values [ $ key ] ; }
Return a value, if it exists.

@param string $key

@return mixed
Return a value if it exists .