code: func absPath(configPath string, defaultPathFn func() (string, error)) (o string, err error) {
  	if len(configPath) > 0 {
  		if o, err = filepath.Abs(configPath); err != nil {
  			err = errors.Wrapf(err, "filepath.Abs of %s failed", configPath)
  			return
  		}
  	} else if defaultPathFn != nil {
  		if o, err = defaultPathFn(); err != nil {
  			err = errors.Wrapf(err, "default path function to compute absPath of %s failed", configPath)
  			return
  		}
  	}
  	return
  }
docs: // absPath computes the absolute path