     // Server state where we kick of requests
     case .fetchingBookingForm(let url, let data, _):
       let dict = data as? [AnyHashable: Any]
-      return requestForm(url, data: dict, forMode: mode, advancing: state)
+      return requestForm(url, data: dict, advancing: state)
       
     // Triggering authentication
     case .authorizing(let form):

  }
  
  
  private static func requestForm(_ url: URL, data: [AnyHashable: Any]? = nil, forMode mode: String, advancing state: TKBookingStateMachine) -> Observable<TKBookingStateMachine> {
    
    return BPKServerUtil.rx
      .requestForm(forBooking: url, postData: data, forMode: mode)
      .map { response in

        let result: TKBookingFormType

  
  /// Send a form-response for a booking URL to the backend, retrieving either a
  /// follow-up form or, if no further action is required, just `nil`.
  fileprivate static func requestForm(forBooking url: URL, postData: [AnyHashable: Any]? = nil) -> Observable<TKBookingResponse> {
    
    return Observable.create { observer in
      
