public function GetIamPolicy(\Google\Cloud\Iam\V1\GetIamPolicyRequest $argument,
      $metadata = [], $options = []) {
        return $this->_simpleRequest('/google.spanner.admin.database.v1.DatabaseAdmin/GetIamPolicy',
        $argument,
        ['\Google\Cloud\Iam\V1\Policy', 'decode'],
        $metadata, $options);
    }