code: public static boolean isValid(
          int yearOfEra,
          HebrewMonth month,
          int dayOfMonth
      ) {
  
          return CALSYS.isValid(HebrewEra.ANNO_MUNDI, yearOfEra, month.getValue(), dayOfMonth);
  
      }
docs: /*[deutsch]
  <p>Pr&uuml;ft, ob die angegebenen Parameter ein wohldefiniertes Kalenderdatum beschreiben. </p>
  
  @param   yearOfEra   the year of era to be checked
  @param   month       the month to be checked
  @param   dayOfMonth  the day of month to be checked
  @return  {@code true} if valid else  {@code false}
  @see     #of(int, HebrewMonth, int)