implementing a stack from scratch in python code example

Example: stack using array python

class ArrayStack:
	def __init__(self):
		self._data = []

	def __len(self):
		return len(self._data)

	def is_empty(self):
		return len(self._data) == 0

	def push(self, e):
		self._data.append(e)

	def pop(self):
		if self.is_empty():
			raise Empty('stack is empty')
		else:
			return self._data.pop()

	def top(self):
		if self.is_empty():
			raise Empty('Stack is empty')
		else:
			return self._data[-1]

	@property
	def data(self):
		return self._data


class Empty(Exception):
	pass