code: def addChild(self, child_id):
          
  
          self.log.debug("Try to add a child <Workitem %s> to current "
                         "<Workitem %s>",
                         child_id,
                         self)
          self._addChildren([child_id])
          self.log.info("Successfully add a child <Workitem %s> to current "
                        "<Workitem %s>",
                        child_id,
                        self)
docs: Add a child to current workitem
  
          :param child_id: the child workitem id/number
              (integer or equivalent string)