code: @Nonnull
    public CalendarIntervalScheduleBuilder withIntervalInMonths (final int intervalInMonths)
    {
      _validateInterval (intervalInMonths);
      m_nInterval = intervalInMonths;
      m_eIntervalUnit = EIntervalUnit.MONTH;
      return this;
    }
docs: Specify an interval in the IntervalUnit.MONTH that the produced Trigger
  will repeat at.
  
  @param intervalInMonths
  the number of months at which the trigger should repeat.
  @return the updated CalendarIntervalScheduleBuilder
  @see ICalendarIntervalTrigger#getRepeatInterval()
  @see ICalendarIntervalTrigger#getRepeatIntervalUnit()