📄️ constructor
Instantiate an empty Deque.
📄️ is_empty
Checks if there are elements in the queue
📄️ peek
Take a look at the element at the front of the queue
📄️ enqueue
Add an item to the back of the queue
📄️ dequeue
Returns and remove the element at the front of the queue
📄️ enqueue_front
Add an item to the front of the queue