// For now, just ignore the `Copy`, we will come back to this point later.
// A `trait` is a lot like interfaces in Java: You define a bunch of functions
// you want to have implemented, and their argument and return types.
// For now, just ignore the `Copy`, we will come back to this point later.
// A `trait` is a lot like interfaces in Java: You define a bunch of functions
// you want to have implemented, and their argument and return types.