This section is just a short introduction to generics; later, we'll cover it in detail.

Generic programming is a style programming that focuses on creating algorithms (and collaterally, data structures) that work on general problems.

The Kotlin way to support generic programming is using type parameters. In a few words, we wrote our code with type parameters and, later on, we pass those types as parameters when we use them. 

Let's take, for example, our Oven interface:

interface Oven {
  fun process(product: Bakeable)
}

An oven is a machine, so we could generalize it more:

interface Machine<T> {
  fun process(product: T)
}

The Machine<T> interface defines a type parameter T and a method process(T).

Now, we can extend it with Oven:

interface Oven: Machine<Bakeable>

Now, Oven is extending Machine with the Bakeable type parameter, so the process method now takes Bakeable as a parameter.