Even though JavaScript is a very dynamic language, sometimes we want to be _extra_ sure that it's not possible to modify an object once it was declared. Luckily, there's a method called `Object.freeze` which allows us to freeze an object so it's not possible to modify it in any way whatsoever once it was initialized. In this lesson we are going to learn how to use `Object.freeze` to ensure that it's not possible to modify an object containing user-specific data