code: private void addFragment(@NonNull final WizardDialog.Builder builder, final int index) {
          Bundle arguments = new Bundle();
          arguments.putInt(DialogFragment.INDEX_EXTRA, index);
          CharSequence title = shouldHeaderBeShown() ? null :
                  String.format(getString(R.string.dialog_tab_text), index);
          builder.addFragment(title, DialogFragment.class, arguments);
      }
docs: Adds a new fragment to a builder, which allows to create wizard dialogs.
  
  @param builder
  The builder, the fragment should be added to, as an instance of the class {@link
  WizardDialog.Builder}
  @param index
  The index of the fragment, which should be added