@receiver(post_save, sender=Comment)
def post_save_comment_count_update(sender, **kwargs):
    comment = kwargs.get('instance')
    comment.commentto.update_count()
Receiver that is called after a comment is saved. Updates num_media and
dataset/ETHPy150Open ExCiteS/geokey/geokey/contributions/models.py/post_save_comment_count_update