Error: Cannot run with sound null safety

[tejaswinidev24]

I am facing this kind of issue whenever I am trying to run the flutter app.

I am using latest version of amazon_cognito_identity_dart

amazon_cognito_identity_dart: ^0.0.22

Error: Cannot run with sound null safety, because the following dependencies
don't support null safety:

 - package:amazon_cognito_identity_dart

For solutions, see https://dart.dev/go/unsound-null-safety
../../Documents/FlutterSDK/flutter/.pub-cache/hosted/pub.dartlang.org/amazon_cognito_identity_dart-0.0.22/lib/sig_v4.dart:142:12: Error: Undefined name 'hex'.
    return hex.encode(value);
           ^^^

[JaredEzz]

You may have already found a solution, but an updated version of this package is available (with null safety!) at https://github.com/furaiev/amazon-cognito-identity-dart-2