code: public final void setBackButtonText(@NonNull final CharSequence text) {
          Condition.INSTANCE.ensureNotNull(text, "The text may not be null");
          Condition.INSTANCE.ensureNotEmpty(text, "The text may not be empty");
          this.backButtonText = text;
          adaptBackButtonText();
      }
docs: Sets the text of the back button, which is shown, when the activity is used as a wizard.
  
  @param text
  The text, which should be set, as an instance of the class {@link CharSequence}. The
  text may neither null, nor empty