docs: public final void getContent (@Nonnull final WPECTYPE aWPEC)
    {
      if (isValidToDisplayPage (aWPEC).isValid ())
      {
        // "before"-callback
        beforeFillContent (aWPEC);
  
        // Create the main page content
        fillContent (aWPEC);
  
        // "after"-callback
        afterFillContent (aWPEC);
      }
      else
      {
        // Invalid to display page
        onInvalidToDisplayPage (aWPEC);
      }
    }