How to know which task fails in chain of tasks?

[Igorsnaki]

Hi all!
Thanks for really helpful lib!

Can anybody help me?

I have chain of 3 tasks ( request to BE) .
Every task/request can return error with code 401 . But I need to know which task failed , because in case 401 I need to perform different steps depending on which task failed.

Code sample:

        let verifyTask = interactor.verifySMSCode(verificationID: verification.codeID, code: smsCode)
        verifyTask.continueOnSuccessWithTask { token -> Task<LoginResponse> in
            self.interactor.saveSMSToken(token: token)
            return self.interactor.login(phone: self.user.phoneNumber)
            }.continueOnSuccessWithTask { loginResponse -> Task<UserDetails> in
                self.interactor.saveAuthData(authData: loginResponse)
                return self.interactor.requestUserDetails(userID: loginResponse.userID)
            }.continueOnSuccessWith(Executor.mainThread) { [weak self] userDetails in
                self?.view.hideActivityIndicator()
                self?.interactor.saveUserDetails(userDetails: userDetails)
                self?.moduleOutput.didLoginSuccessfuly()
            }.continueOnErrorWith(Executor.mainThread) { [weak self] error in
                self?.view.hideActivityIndicator()
                if (error as NSError).code == 401 {
                   // every of 3 requests / task can return me error code == 401 
                   // How can I understand which of previous 3 task failed??? 
                }
                self?.view.showError(title: nil, message: error.localizedDescription, buttonTitile: "OK")
        }

Are there any ways to separate which task are failed in continueOnErrorWith block ??

P.S. I want to use chain of tasks to make code look better.
I don't wont to use :

        verifyTask.continueWith { task in
            if let result = task.result {
                self.interactor.login(phone: user.phoneNumber).continueWith { task in
                    self.interactor.requestUserDetails(userID: result.userID).continueWith {
                        if ///
                    }
                }
            } else if let err = task.error {
                //
            }
        }