def add(self, item):
"""Adds item to the rear of the queue."""
newNode = Node(item, None)
if self.is_empty():
self._front = newNode
else:
self._rear.next = newNode
self._rear = newNode
self._size += 1
def push(self, item):
"""Adds item to the top of the stack."""
self._items = Node(item, self._items)
self._size += 1