What this means is we are going to create a custom package named `rand` that will utilize the functionality provided by the [math/rand](https://golang.org/pkg/math/rand/) package in order to create our own functions, and mask most of the implementation details. That way the rest of our code doesn’t need to concern itself with the implementation details of generating random strings, but can instead simply call functions like `rand.String(10)` to get a random string with 10 characters in it.