code: func (v *VersionFile) Write(vp *EtcdVersionPair) error {
  	data := []byte(fmt.Sprintf("%s/%s", vp.version, vp.storageVersion))
  	return ioutil.WriteFile(v.path, data, 0666)
  }
docs: // Write creates or overwrites the contents of the version.txt file with the given EtcdVersionPair.