code: @Override public void setUniqueID(Integer uniqueID)
     {
        ProjectFile parent = getParentFile();
  
        if (m_uniqueID != null)
        {
           parent.getCalendars().unmapUniqueID(m_uniqueID);
        }
  
        parent.getCalendars().mapUniqueID(uniqueID, this);
  
        m_uniqueID = uniqueID;
     }
docs: Modifier method to set the unique ID of this calendar.
  
  @param uniqueID unique identifier