Error Trace : Invalid argument(s) (onError): The error handler of Future.catchError must return a value of the future's type

Invalid argument(s) (onError): The error handler of Future.catchError must return a value of the future's type

Traces :

0 _FutureListener.handleError (dart:async/future_impl.dart:262) 1 Future._propagateToListeners.handleError (dart:async/future_impl.dart:960) 2 Future._propagateToListeners (dart:async/future_impl.dart:981) 3 Future._completeErrorObject (dart:async/future_impl.dart:738) 4 Future._completeError (dart:async/future_impl.dart:742) <asynchronous suspension>