public static function findByExternalId($externalId)
    {
        if (gettype($externalId) == 'string') {
            $externalId = ['external_id' => $externalId];
        }

        $response = static::all($externalId);

        if (is_null($response)) {
            return null;
        } else {
            return $response->first();
        }
    }