Jose\Object\JWKInterface::has PHP Метод

    public function has($key);

 /**
  * @param JWKInterface $key
  */
 private function checkKey(JWKInterface $key)
 {
     Assertion::eq($key->get('kty'), 'OKP', 'Wrong key type.');
     Assertion::true($key->has('x'), 'The key parameter "x" is missing.');
     Assertion::true($key->has('crv'), 'The key parameter "crv" is missing.');
     Assertion::inArray($key->get('crv'), ['Ed25519'], 'Unsupported curve');
 }