Proper way to index __pycache__ (bytecode) files?

Hi,

I'd like to get some advice on how to add bytecode files when you cannot 
use (?) autoplist and/or distutils. I've been scanning the tree for a 
solution but I can't find one seems to work and Ports tree documentation 
is a bit sparse on the matter. Some ports use py3kplist but I my 
attempts to figure out what "a Python 2.x packaging list" actually looks 
like others ports just adds files to the temporary plist variable which 
seems a bit hacky. Currently I have this 
https://cgit.freebsd.org/ports/tree/textproc/py-libxml2/Makefile?id=25c952626c32a1830793a770b8f401a7d5370905 
which works fine for all versions except for 3.7 due to 
https://cgit.freebsd.org/ports/tree/Mk/Uses/python.mk#n474 . I could 
define it for 3.7 in the port but I'm not sure that's a good idea so any 
advice would be appreciated.

Best regards,
Daniel