'Remove all tags from the handler.
Args:
category (str, optional): The Tag category to limit the
request to. Note that `None` is the valid, default
category.'

def clear(self, category=None):

    query = {('%s__id' % self._model): self._objid, 'tag__db_model': self._model, 'tag__db_tagtype': self._tagtype}
    if category:
        query['tag__db_category'] = category.strip().lower()
    getattr(self.obj, self._m2m_fieldname).through.objects.filter(**query).delete()
    self._cache = {}
    self._catcache = {}
    self._cache_complete = False
