def active(self):
        assert_soft_delete()
        return self.filter(deleted=False)
get a tag corresponding to a target, if it's clear the target "owns" the tag.
dataset/ETHPy150Open django-notifications/django-notifications/notifications/models.py/NotificationQuerySet.active--crossover with--dataset/ETHPy150Open vimeo/graph-explorer/graph_explorer/preferences_color.py/get_unique_tag_value