def METHOD_NAME(self, queryset: "QuerySet") -> None:
    """
    Called internally to generate prefetching query.
    :param queryset: Custom QuerySet to use for prefetching.
    :raises OperationalError: If field does not exist in model.
    """
    first_level_field, __, forwarded_prefetch = self.relation.partition("__")
    if first_level_field not in queryset.model._meta.fetch_fields:
        raise OperationalError(
            f"relation {first_level_field} for {queryset.model._meta.db_table} not found"
        )
    if forwarded_prefetch:
        if first_level_field not in queryset._prefetch_map.keys():
            queryset._prefetch_map[first_level_field] = set()
        queryset._prefetch_map[first_level_field].add(
            Prefetch(forwarded_prefetch, self.queryset, to_attr=self.to_attr)
        )
    else:
        queryset._prefetch_queries.setdefault(first_level_field, []).append(
            (self.to_attr, self.queryset)
        )