@Nonnull
 static WizardFlow newFirstTimeWizardFlow() {
   final List<WizardStep> wizardSteps = new ArrayList<WizardStep>();
   for (WizardStep wizardStep : CalculatorWizardStep.values()) {
     if (wizardStep.isVisible()) {
       wizardSteps.add(wizardStep);
     }
   }
   return new ListWizardFlow(wizardSteps);
 }
 @Nonnull
 static WizardFlow newDefaultWizardFlow() {
   final List<WizardStep> wizardSteps = new ArrayList<WizardStep>();
   for (WizardStep wizardStep : CalculatorWizardStep.values()) {
     if (wizardStep != welcome && wizardStep != last && wizardStep.isVisible()) {
       wizardSteps.add(wizardStep);
     }
   }
   return new ListWizardFlow(wizardSteps);
 }