code: def set_identifiertext(self, index):
          
          dr = QtCore.Qt.DisplayRole
          t = index.model().index(index.row(), 17, index.parent()).data(dr)
          if t is None:
              t = -1
          else:
              t = t+1
          self.identifier_lb.setText("#%s" % t)
docs: Set the identifier text on the identifier_lb
  
          :param index: the index
          :type index: :class:`QtGui.QModelIndex`
          :returns: None
          :rtype: None
          :raises: None