title: Error: The argument type 'Uint8List?' can't be assigned to the parameter type 'Iterable<int>
body: <p>i am this as i convert to Null- safety, and i keep getting this error</p>
  <p><a href="https://i.stack.imgur.com/iljFa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/iljFa.png" alt="error" /></a></p>
  <p>here is my code</p>
  <pre><code>try {
        final AuthorizationResult appleResult =
            await TheAppleSignIn.performRequests([
          AppleIdRequest(requestedScopes: [Scope?.email, Scope?.fullName])
        ]);
        if (appleResult.error != null) {
          // handle errors from Apple here
        }
  
        final AuthCredential credential = OAuthProvider('apple.com').credential(
          accessToken:
              String.fromCharCodes(appleResult.credential!.authorizationCode),//here the error coming out.... i have also try Uint8List.fromList but still showing the error
          idToken: String.fromCharCodes(appleResult.credential!.identityToken),//here the error coming out.... i have also try Uint8List.fromList but still showing the error
        );
        final firebaseResult = await auth.signInWithCredential(credential);
        users = firebaseResult.user;
        if (users == null) {
          return false;
        }
        return true;
      } catch (error) {
        print(error);
        return false;
      }
  </code></pre>
  <p>i have also try</p>
  <p><strong>Uint8List.from()</strong></p>