Stack

from my_array_deque import ArrayDeque
from my_linked_list import LinkedList

class Stack:
    def __init__(self, a_type = None):
        ''' Initalises either a linked list or deque '''
        self.type = a_type
        if self.type == 'array':
            self.stack = ArrayDeque()
        elif self.type == 'linked':
            self.stack = LinkedList()
        else:
            raise TypeError

    def __str__(self):
       return self.stack.__str__()

    def push(self, value):
        return self.stack.push_back(value)

    def pop(self):
        return self.stack.pop_back()

    def get_size(self):
        return self.stack.get_size()