'If versioning is being used, then determine any API version for the
incoming request. Returns a two-tuple of (version, versioning_scheme)'

def determine_version(self, request, *args, **kwargs):

    if (self.versioning_class is None):
        return (None, None)
    scheme = self.versioning_class()
    return (scheme.determine_version(request, *args, **kwargs), scheme)
