Defining an Enum

# Introduction

Welcome to **Defining an Enum**. This lab is a part of the [Rust Book](https://doc.rust-lang.org/book/). You can practice your Rust skills in LabEx.

In this lab, we will be defining an enum called `IpAddrKind` to represent the possible kinds of IP addresses, including version four (`V4`) and version six (`V6`).