deque.py

from collections import deque

class Deque:
    def __init__(self):
        self.items = deque()

    def add_front(self, item):
        self.items.appendleft(item)

    def add_rear(self, item):
        self.items.append(item)

    def remove_front(self):
        if not self.is_empty():
            return self.items.popleft()

    def remove_rear(self):
        if not self.is_empty():
            return self.items.pop()

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

    def size(self):
        return len(self.items)