createCredential method Null safety

Future<String?> createCredential(
  1. String address
)

Implementation

Future<String?> createCredential(String address) async {
  try {
    final options = MakeCredentialOptions.fromJson(jsonDecode(makeCredentialJson));
    options.userEntity = UserEntity(
      id: Uint8List.fromList(address.codeUnits),
      displayName: address,
      name: address,
    );

    final attestation = await _auth.makeCredential(options);
    _credentials.add(CredentialData(address, attestation));
    return attestation.getCredentialIdBase64();
  } on AuthenticatorException catch (e) {
    if (kDebugMode) {
      print(e);
    }
    return null;
  }
}