wat.py

# If this is the interface:

SiteNavigation(site).as_dict()

# that means we have to have a site object to build a site nav object.
# That's fine within the Site object.

# My point was that if (someday in the future) we need to build a nav object but we only have a site id,
# instead of doing this:

SiteNavigation(Site.objects.get(site_id)).as_dict()

# we could extend the interface to support this:

SiteNavigation.for_site_id(site_id).as_dict()

# We don't need this for what we're talking about.
# I was only making a case that it's ok to accept the object instead of the id since it suits our needs for now.