code: func (f *fileCloser) Close() error {
  	err := f.f.Close()
  	if err != nil {
  		return fmt.Errorf(
  			"Could not close file %v: %v",
  			f.path,
  			err,
  		)
  	}
  	return nil
  }
docs: // Close - add file path information to closing a file