code: private ProjectCalendar deriveResourceCalendar(Integer parentCalendarID)
     {
        ProjectCalendar calendar = m_project.addDefaultDerivedCalendar();
        calendar.setUniqueID(Integer.valueOf(m_project.getProjectConfig().getNextCalendarUniqueID()));
        calendar.setParent(m_project.getCalendarByUniqueID(parentCalendarID));
        return calendar;
     }
docs: Derive a calendar for a resource.
  
  @param parentCalendarID calendar from which resource calendar is derived
  @return new calendar for a resource