code: def get_row_by_task_id(self, task_id):
          '''返回这个任务的TreeModelRow, 如果不存在, 就返回None.'''
          for row in self.liststore:
              if row and row[TASKID_COL] == task_id:
                  return row
          return Nonf get_row_by_task_id(self, task_id):
          '''返回这个任务的TreeModelRow, 如果不存在, 就返回None.'''
          for row in self.liststore:
              if row and row[TASKID_COL] == task_id:
                  return row
          return None
docs: 返回这个任务的TreeModelRow, 如果不存在, 就返回None.