private function getProperty($key)
    {
        return array_key_exists($key, $this->fields) ? $this->fields[$key] : null;
    }
private function getProperty($key)
    {
        return array_key_exists($key, $this->fields) ? $this->fields[$key] : null;
    }
private function getProperty ( $ key ) { return array_key_exists ( $ key , $ this -> fields ) ? $ this -> fields [ $ key ] : null ; }
Get dynamic property.

@param $key
@return null
Get dynamic property .