stack.py

def createStack():
	return []

def isEmpty(stack):
	if len(stack)==0:
		return True
	else:
		return False

def push(stack, element):
	stack.append(element)

def pop(stack):
	if isEmpty(stack):
		raise ValueError("Stack is Empty")
	else:
		stack.pop()

def top(stack):
	if isEmpty(stack):
		print("Stack is Empty")
		return None
	else:
		return stack[-1]