old_contents: # Create queue using a list
  
  class Queue:
  	def __init__(self, head=None):
  		self.storage = [head]
  
  	def enqueue(self, new_element): # add to back
  		self.storage.append(new_element)
  
  	def dequeue(self): # remove from front
  		return self.storage.pop(0)
  
  	def peek(self): # take a look at the first in line
  		return self.storage[0]
  
new_contents: # Create queue using a list
  
  class Queue:
  	def __init__(self, head=None):
  		self.storage = [head]
  
  	def enqueue(self, new_element): # add to back
  		self.storage.append(new_element)
  
  	def dequeue(self): # remove from front
  		return self.storage.pop(0)
  
  	def peek(self): # take a look at the first in line
  		return self.storage[0]
  
  
  # test case
  test_queue = Queue(1)
  test_queue.enqueue(2)
  test_queue.enqueue(3)
  
  print test_queue.peek() # prints 1
  print test_queue.dequeue() # prints 1
  test_queue.enqueue(4)
  print test_queue.dequeue() # prints 2
  print test_queue.dequeue() # prints 3
  print test_queue.dequeue() # prints 4
  test_queue.enqueue(5)
  print test_queue.peek() # prints 5
  
subject: Add test case