public function removeTerms($vocabulary_id = null)
    {
        if ($vocabulary_id === null) {
            return $this->getTaxonomyQuery()->delete();
        }

        if (!is_numeric($vocabulary_id)) {
            $vocabulary_id = T::vocabulary($vocabulary_id);
        }

        return $this->getTaxonomyQuery()->whereIn('term_id', function ($query) use ($vocabulary_id) {
            $query->select('id')->where('vocabulary_id', $vocabulary_id)->from((new TermContainer)->getTable());
        })->delete();
    }