[CentOS] Python search path

Hello,

Working on a project to create clean spec files for libbitcoin for 
CentOS 7 (and eventually I want them to work in Fedora 25+ too)

These spec files must work with the user defines an alternate %{_prefix} 
before building them.

This means that python components would be installed in /opt/libbitcoin 
(or whatever) instead of in /usr so %{python2_sitelib} and 
%{python2_sitearch} no longer would apply.

sys.path.append looks like the way to tell python about a new path to 
look for stuff, but I'm guessing there are guidelines somewhere for how 
that is suppose to properly done from within spec files.

Unfortunately I can't find them, and search engines are getting harder 
and harder to use to find technical related information, always changing 
my query and showing me completely unrelated results.

Anyway I didn't see anything in the Fedora packaging guidelines for 
python, that seems to be targeting a prefix of /usr

Thanks for any links or suggestions.