[O] Updating :PROPERTIES: :ACTUAL: with total clocked time

[Shakthi Kannan]

Hi,

I would like to know how we can update the :ACTUAL: field in
:PROPERTIES: for a DONE task with the total clocked time. A MWE:

=== sample.org ===

* IN_PROGRESS Task A
    :PROPERTIES:
    :ESTIMATED: 4.0
    :ACTUAL:
    :END:
    :LOGBOOK:
    CLOCK: [2017-01-26 Thu 19:00]--[2017-01-26 Thu 19:30] =>  0:30
    CLOCK: [2017-01-26 Thu 13:00]--[2017-01-26 Thu 14:30] =>  1:30
    :END:

=== END ===

As soon as I mark the above task as DONE, the total clocked time needs
to be updated in the :ACTUAL: field as shown below:

=== sample.org ===

* DONE Task A
    :PROPERTIES:
    :ESTIMATED: 4.0
    :ACTUAL: 2.0
    :END:
    :LOGBOOK:
    CLOCK: [2017-01-26 Thu 19:00]--[2017-01-26 Thu 19:30] =>  0:30
    CLOCK: [2017-01-26 Thu 13:00]--[2017-01-26 Thu 14:30] =>  1:30
    :END:

=== END ===

How can this be achieved?

SK

-- 
Shakthi Kannan
http://www.shakthimaan.com