class LinkedQueue:
def __init__(self):
self._items = LinkedList()
def is_empty(self):
return len(self._items) == 0
def __len__(self):
return len(self._items)
def __iter__(self):
iter(self._items)
def clear(self):
self._items = LinkedList()
def add_front(self, item):
self._items.append_head(item)
def add_rear(self, item):
self._items.append(item)
def remove_front(self):
return self._items.pop_head()
def remove_rear(self):
return self._items.pop_tail()
