new_contents: """
  Implementation of priority queue
  """
  
  class PriorityQueueNode:	
  	def __init__(self, data, priority):
  		self.data = data
  		self.priority = priority
  
  	def __repr__(self):
  		return str(self.data) + ": " + str(self.priority)
  
  class PriorityQueue:
  	def __init__(self):
  		self.priority_queue_list = []
  
  	def size(self):
  		return len(self.priority_queue_list)
  
  	def insert(self, node):
  		# if queue is empty
  		if self.size() == 0:
  			self.priority_queue_list.append(node)
  		else:
  			 # traverse the queue to find the right place for new node
  			 for index, current in enumerate(self.priority_queue_list):
  			 	if current.priority < node.priority:
  			 		# if we have traversed the complete queue
  			 		if index == self.size() - 1:
  			 			# add new node at the end
  			 			self.priority_queue_list.insert(index + 1, node)
  			 		else:
  			 			continue
  			 	else:
  			 		self.priority_queue_list.insert(index, node)
  			 		return True
  
  	def delete(self):
  		# remove the first node from the queue
  		return self.priority_queue_list.pop(0)
  										
subject: Add priority queue implementation using lists