public function getAuthKeyRules()
    {
        if (!is_string($this->authKeyAttribute) || empty($this->authKeyAttribute)) {
            return [];
        }
        if (empty($this->authKeyRules)) {
            $this->authKeyRules = [
                [[$this->authKeyAttribute], 'required'],
                [[$this->authKeyAttribute], 'string', 'max' => 40],
            ];
        }
        return $this->authKeyRules;
    }