public function nullifySettings(): self 	{ 		setting()->fill([ 			'registration_role_id' => setting('registration_role_id') === $this->getKey() ? null : setting('registration_role_id'), 			'registration_api_role_id' => setting('registration_api_role_id') === $this->getKey() ? null : setting('registration_api_role_id'), 		]) 		->save();  		return $this; 	}