This is backwards compatibility to django-filter 1.1 (required for Python 2.7).
        In 1.1 `filter_queryset` does not call `get_filterset` or `get_filterset_kwargs`.

def filter_queryset(self, request, queryset, view):
        """
        This is backwards compatibility to django-filter 1.1 (required for Python 2.7).
        In 1.1 `filter_queryset` does not call `get_filterset` or `get_filterset_kwargs`.
        """
        # TODO: remove when Python 2.7 support is deprecated
        if VERSION >= (2, 0, 0):
            return super(DjangoFilterBackend, self).filter_queryset(request, queryset, view)

        filter_class = self.get_filter_class(view, queryset)

        kwargs = self.get_filterset_kwargs(request, queryset, view)
        self._validate_filter(kwargs.pop('filter_keys'), filter_class)

        if filter_class:
            return filter_class(kwargs['data'], queryset=queryset, request=request).qs

        return queryset