I attempted to use the retryWhen function to renew my token, but unfortunately, it threw an error Value of type 'any Cancelable' has no member 'retryWhen'

task is URLSessionTask

return Observable.create { observer in
..........
            return Disposables.create {
                self.task?.cancel()
            }.retryWhen { error -> Observable<Error> in
                return error.flatMapLatest { error -> Observable<Error> in
                    return refreshToken()
                        .flatMapLatest { response -> Observable<Error> in
                            return Observable.error(ResponseErrorCode.FAILED)
                        }
                }
            }
}

Could you please guide me on how to fix it? Thank you very much!