def get_last_tid(self):
        try:
            spec = {'tid': {'$gt': 0}}
            sort = [('tid', -1)]
            row = self.db.docs.find_one(spec, sort=sort)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return row['tid']
        return 0
def on_lower_bound_checked_changed(self):
        if self.ui.checkBoxLowerBound.isChecked():
            self.ui.spinBoxLowerBound.setEnabled(True)
            self.ui.spinBoxBoundaryNumber.setEnabled(True)
        elif not self.ui.checkBoxUpperBound.isChecked():
            self.ui.spinBoxLowerBound.setEnabled(False)
            self.ui.spinBoxBoundaryNumber.setEnabled(False)
        else:
            self.ui.spinBoxLowerBound.setEnabled(False)