exception - no one knows!

try:
  try:
    self.DBHelper.SubCompany_MappingDeleteStdByCID(cursor, ...)
    if self.Mode == SUBCOMPANYMAPPINGDIALOG_MODE_ADD:
      self.DBHelper.SubCompany_MappingAdd(cursor, ...)
    else:
      self.DBHelper.SubCompany_MappingReplace(cursor, ...)
      DB.commit()
  except:
    DB.rollback()   
finally:
  cursor.close()    

From my point of view I'd love to know that exception occured!