'Given a queryset, filter it with whichever filter backend is in use.
You are unlikely to want to override this method, although you may need
to call it either from a list view, or from a custom `get_object`
method if you want to apply the configured filtering backend to the
default queryset.'

def filter_queryset(self, queryset):

    for backend in list(self.filter_backends):
        queryset = backend().filter_queryset(self.request, queryset, self)
    return queryset
