Over-writing of post_apply_hook by some HSI_Events

[tbhallett]

There are some instance of disease module writing instances of HSI_Events with a post_apply_hook method defined. This will over-write the method of the same name in the base class, preventing the functionality contained therein to operate (post_apply_hook in HSI_Event base class). It was a sort of "unwritten rule" (!) that the post_apply_hook part of an HSI_Event is reserved for use by the HSI_Event itself.

Examples of HSI_Event instance over-writing this method are:

TLOmodel/src/tlo/methods/tb.py

Line 2236 in 67c8058

def post_apply_hook(self):

TLOmodel/src/tlo/methods/contraception.py

Line 1215 in 67c8058

def post_apply_hook(self):

There may be others...!

A simple fix would be for this logic to be placed at the end of the apply function in the respective HSI_Event.

But, a better fix would be allow the disease module do over-write the post_apply_hook method and create another method that is only called by the HealthSystem. e.g. in the HSI_Event base class:

• put the current content of the post_apply_hook into _run_after_hsi_event,
• over-write run (from the Event base class) to run apply, then post_apply_hook, then _run_after_hsi_event

[matt-graham]

Another option would be for any classes which do overwrite the base class implementation of post_apply_hook to have to call the base class implementation within their implementation using

    super().post_apply_hook()

Overall though I think your proposed approach @tbhallett of creating a new 'private' method _run_after_hsi_event is probably nicer as it doesn't rely on people remembering to call the base class method in their implementation.

[tbhallett]

Thanks Matt. I'll give it a go