class Stack
        declare internalList

        // constructor
        def Stack()
                internalList = list()
        end

        def push(val)
                internalList.append(val)
        end

        def pop()
                val = internalList[int(len($internalList) - 1)]
                internalList.remove(val)

                return val
        end

        def empty()
                return len(internalList) = 0
        end
end