How to set the sum of story points of subtasks whose status is not "Done" to Story point of Story

[Suguru Watanabe _Woven Alpha_]

I would like to set the sum of story points of subtasks whose status is not "Done" to Story point of (their parent) Story when the status of each subtask is changed to "Done".

I tried to set the configuration of Jira Automation as following, but that did not work as expected, the story point of parent story was not changed. 

(1)trigger:  field value chaned, the status of all issues
(2)issue fields condition: status is "Done"

(3)branch compornent: Parent
(4)JQL condtion: issuetype in (subtask) and "parent" = "{{issue.id}}"
(5)edit issue: Story Point,  {{lookupissues.Story Points.sum}}

If I would like to set the sum of story points of all subtasks regardless of status, I know (4) above is not needed and I only have to write following in (5).
{{issue.subtasks.Story Points.sum}}

Could someone let me know how to solve it.
Thank you.

[Nic Brough -Adaptavist-]

Welcome to the Atlassian Community!

I would "solve" this by not doing it at all.  It's not a good way to use story points, and certainly won't work if you're working in an Agile fashion. 

Could you explain what you are trying to report on, and how it lead you to this idea?