public function getRates()
 {
     $file = file_get_contents(self::URL);
     $xml = new \SimpleXMLElement($file);
     Rates::setRate('EUR', 1);
     foreach ($xml->Cube->Cube->Cube as $item) {
         $currency = (string) $item->attributes()->currency;
         $rate = (double) $item->attributes()->rate;
         if (isset($currency) && isset($rate)) {
             Rates::setRate($currency, $rate);
         }
     }
 }