Dumplie\CustomerService\Domain\Exception\PaymentNotFoundException::byId PHP Method

    public static function byId(PaymentId $paymentId) : PaymentNotFoundException
    {
        return new self(sprintf('Payment with id "%s" does not exists.', (string) $paymentId));
    }

 /**
  * @param PaymentId $paymentId
  *
  * @return Payment
  * @throws PaymentNotFoundException
  */
 public function getById(PaymentId $paymentId) : Payment
 {
     if (!array_key_exists((string) $paymentId, $this->payments)) {
         throw PaymentNotFoundException::byId($paymentId);
     }
     return $this->payments[(string) $paymentId];
 }