def METHOD_NAME(sender: Type[Employment], instance: Employment = None, **kwargs):
    """Ensure related cache keys are removed to prevent access to old data"""
    if instance is None:
        return
    # Cache keys of akvo.rest.viewsets.PublicProjectViewSet.projects_filter_for_non_privileged_users
    from akvo.rest.viewsets import make_projects_filter_cache_prefix
    try:
        user = instance.user
        keys = [
            key for key in akvo_cache.list_cache_keys()
            if key.startswith(make_projects_filter_cache_prefix(user))
        ]
        if keys:
            logger.info("deleting %s keys of user %s(%s)", len(keys), user, user.id)
            cache.delete_many(keys)
    except Exception as exc:
        logger.warning("Cannot invalidate cache: %s", exc)