Doc or example about conda custom build?

[Marco Sulla]

Sorry for being maybe a little OT. I tried to get help from other Conda
users, from chat and from the mailing list without success.

I would add a custom build on my conda package. Is there somewhere a doc or
an example about it?

(Specifically, I want to pass a custom parameter to the setup.py that lets
me package only the pure py version of the code.)