stack.py

class Stack:
    def __init__(self):
        self.STACK = []

    def push(self, element):
        self.STACK.append(element)
        return self.STACK

    def check_empty(self):
        return len(self.STACK) == 0

    def pop(self):
        if self.check_empty():
            return "stack is empty"
        return self.STACK.pop()

    def peek(self):
        return self.STACK