new_contents: '''
  Implement Queue data structure using two stacks
  
  '''
  
  from stack import Stack
  
  class QueueUsingTwoStacks(object):
  	def __init__(self):
  		'''
  		Initialize Queue
  
  		'''
  		self.stack1 = Stack()
  		self.stack2 = Stack()
  
  	def __len__(self):
  		'''
  		Return number of items in Queue
  
  		'''
  		return len(self.stack1) + len(self.stack2)
  
  	def enqueue(self,value):
  		'''
  		Enqueue item to queue
  
  		'''
  		self.stack1.push(value)
  
  	def dequeue(self):
  		'''
  		Dequeue item from queue
  
  		'''
  		if not self.stack2.is_empty():
  			return self.stack2.pop()
  		while not self.stack1.is_empty():
  			self.stack2.push(self.stack1.pop())
  		return self.stack2.pop()
  
subject: Add Queue implementation using two stacks