How does Ruby work with Test Automation Page Object Pattern

The key to page object pattern is a certain page can do certain things and other pages can do others things. This works well with Java's encapsulation.

However, with Ruby's flexibity I don't see how this can work: -There’s no static type checking. -Variable names are just labels. They don’t have a type associated with them. -There are no type declarations. You just assign to new variable names as-needed and they just “spring up” (i.e. a = [1,2,3] rather than int[] a = {1,2,3};). -There’s no casting. Just call the methods. Your unit tests should tell you before you even run the code if you’re going to see an exception.

Can someone explain?