code: func MustParseEtcdVersionPair(s string) *EtcdVersionPair {
  	pair, err := ParseEtcdVersionPair(s)
  	if err != nil {
  		panic(err)
  	}
  	return pair
  }
docs: // MustParseEtcdVersionPair parses a "<version>/<storage-version>" string to an EtcdVersionPair
  // or panics if the parse fails.