def METHOD_NAME(user, tags):
    """
    returns total quest xp related to user and tags
    Args:
        user (UserModel): user object
        tags (list[str], Queryset<Tag>): a queryset or list of Tag objects
    Returns:
        int: total badge xp related to user and tags
    """
    # sum can be none since aggregate() will always return a dictionary of keys of whatever arg you put in.
    # if there are no badges or quests linked to the user, aggregate will return a dictionary like: { 'badge__xp__sum': None }
    return get_badge_assertion_by_tags(user, tags).aggregate(Sum("badge__xp"))['badge__xp__sum'] or 0