code: func Update(name string, actualData []byte) error {
  	if err := ensureDir(filepath.Dir(goldenFileName(name))); err != nil {
  		return err
  	}
  
  	return ioutil.WriteFile(goldenFileName(name), actualData, FilePerms)
  }
docs: // Update will update the golden fixtures with the received actual data.
  //
  // This method does not need to be called from code, but it's exposed so that it
  // can be explicitly called if needed. The more common approach would be to
  // update using `go test -update ./...`.