code: protected function configureDefaultData(array $data)
      {
          foreach ($this->_REQUIRED_DATA as $property => $value) {
              if (!isset($data[$property]) && $value !== null) {
                  $data[$property] = $value;
              }
          }
          return $data;
      }
docs: Configure Defaults on a Data array based on the Required Data property
  @param array $data
  @return array