Define self._lazy_collection according to filters.

def _add_filters(self, **filters):
        """Define self._lazy_collection according to filters."""
        for key, value in filters.items():
            if self._field_is_pk(key):
                pk = self.cls.get_field('pk').normalize(value)
                self._lazy_collection['pks'].add(pk)
            else:
                # store the info to call the index later, in ``_prepare_sets``
                # (to avoid doing extra work if the collection is never called)
                index, suffix, extra_field_parts = self._parse_filter_key(key)
                parsed_filter = ParsedFilter(index, suffix, extra_field_parts, value)
                self._lazy_collection['sets'].append(parsed_filter)

        return self