simple swift stack

import Foundation

class Stack<T> {
    var storage = [T]()
    
    func push(_ thing: T) {
        storage.append(thing)
    }
    
    func pop() -> T {
        // declaring it a programmer error if trying to pop an empty stack
        return storage.popLast()!
    }
    
    func isEmpty() -> Bool {
        return storage.count == 0
    }
}

let intStack = Stack<Int>()

intStack.push(5)
intStack.push(10)
intStack.pop()
intStack.pop()