Error while adding a new child to a workitem

[Shruthi-KRamesh]

client = RTCClient(server, username = username, password = password, ends_with_jazz = True)
workitem = client.getWorkitem(133350)

workitem.addChild(133451)

the code works fine until getting a workitem, and when I try to add a child to it, I get the below error.

'NoneType' object is not iterable

I can assure that the workitem I am willing to add as a child already exists.

[ameyyadav09]

The error is not in the addChild method of the workitem. it's in the _addChildren method, cur_child_ids = [cur_child.identifier for cur_child in cur_children] at this line when we say cur_child.identifier, we will get error if cur_child is None. This happens if the workitem doesn't have any children initially.

[dixudx]

@ameyyadav09 Thanks for your PR. This bug is duplicate with #95, which has already been fixed.