old_contents: #! /usr/bin/env python
  # Stack Python file for Efrain, Mark and Henry
  
  class Node(object):
      """A Node Class representing a Node in a queue.
      Each node has a pointer to the next node and a value.
      """
  
      def __init__(self, value, back=None):
          """Create Node with value and optional pointer.
          If no pointer is specified, pointer is set to None.
          """
          self.point_previous = back
          self.value = value
  
  
  class Queue(object):
      """Class defining a queue data structure."""
  
      def __init__(self):
          """Create a queue with a pointer to the front and back of an empty queue
          and set count to zero to keep track of size"""
          self.front = None
          self.back = None
          self.count = 0
  
      def enqueue(self, value):
          """Adds a node with the value to the back of the queue"""
          old_back = self.back
          self.back = Node(value)  # set  Nodes next to the old back
          if self.size() > 0:  # if any Nodes: set back previous to current Node
              old_back.point_previous = self.back
          else:  # adding to an empty, than define front
              self.front = self.back
          self.count += 1
  
      def dequeue(self):
          """Returns a value of the front node and removes it from the queue
          If the qpopulated_queueueue is empty, return AttributeError."""
          try:
              val = self.front.value
              self.front = self.front.point_previous
          except AttributeError:
              raise AttributeError(u"Queue is empty")
          self.count -= 1
          return val
  
      def size(self):
          """Returns the size of the queue"""
          return self.count
  
new_contents: #! /usr/bin/env python
  # Queue Python file for Efrain, Mark and Henry
  
  
  class Node(object):
      """A Node Class representing a Node in a queue.
      Each node has a pointer to the next node and a value.
      """
  
      def __init__(self, value, back=None):
          """Create Node with value and optional pointer.
          If no pointer is specified, pointer is set to None.
          """
          self.point_previous = back
          self.value = value
  
  
  class Queue(object):
      """Class defining a queue data structure."""
  
      def __init__(self):
          """Create a queue with a pointer to the front and back of an empty queue
          and set count to zero to keep track of size"""
          self.front = None
          self.back = None
          self.count = 0
  
      def enqueue(self, value):
          """Adds a node with the value to the back of the queue"""
          old_back = self.back
          self.back = Node(value)  # set  Nodes next to the old back
          if self.size() > 0:  # if any Nodes: set back previous to current Node
              old_back.point_previous = self.back
          else:  # adding to an empty, than define front
              self.front = self.back
          self.count += 1
  
      def dequeue(self):
          """Returns a value of the front node and removes it from the queue
          If the qpopulated_queueueue is empty, return AttributeError."""
          try:
              val = self.front.value
              self.front = self.front.point_previous
          except AttributeError:
              raise AttributeError(u"Queue is empty")
          self.count -= 1
          return val
  
      def size(self):
          """Returns the size of the queue"""
          return self.count
  
subject: Fix docstring error.