old_contents: from ed2d.physics import rectangle
  from ed2d.physics import quadtree
  
  class PhysEngine(object):
  
      def __init__(self):
          # I would love to have width and height as global constants
          self.quadTree = quadtree.QuadTree(0, rectangle.Rectangle(0.0, 0.0, width=800, height=600, flag='QT'))
          self.quadTree.clear()
          self.pObjects = []
          self.returnObjects = []
  
      def simulate(self, delta):
          '''Update all the objects'''
          # Update the quad tree
          self.quadTree.clear()
          for item in self.pObjects:
              self.quadTree.insert(item)
  
          # Pass this for a while, this basically add velocity to objects
          # But is kinda of a stupid way to do
          '''
          for i in range(len(self.pObjects)):
              self.pObjects[i].update(delta)
          '''
  
          # Run collision check
          self.collisions()
  
      def collisions(self):
          objects = []
          self.quadTree.retriveAll(objects)
          for x in range(len(objects)):
              obj = []
              self.quadTree.findObjects(obj, objects[x])
              for y in range(len(obj)):
                  objects[x].getCollisionModel().intersect(obj[y].getCollisionModel())
              del obj[:]
          del objects[:]
  
      def addObject(self, p_object):
          self.quadTree.insert(p_object)
          self.pObjects.append(p_object)
  
      def getObject(self, index):
          return self.pObjects[index]
  
      def getLength(self):
          return len(self.pObjects)
new_contents: from ed2d.physics import rectangle
  from ed2d.physics import quadtree
  
  class PhysEngine(object):
  
      def __init__(self):
          # I would love to have width and height as global constants
          self.quadTree = quadtree.QuadTree(0, rectangle.Rectangle(0.0, 0.0, width=800, height=600, flag='QT'))
          self.quadTree.clear()
          self.pObjects = []
          self.returnObjects = []
  
      def simulate(self, delta):
          '''Update all the objects'''
          # Update the quad tree
          self.quadTree.clear()
          for item in self.pObjects:
              self.quadTree.insert(item)
  
          # Pass this for a while, this basically add velocity to objects
          # But is kinda of a stupid way to do
          # for i in range(len(self.pObjects)):
          #     self.pObjects[i].update(delta)
  
          # Run collision check
          self.collisions()
  
      def collisions(self):
          objects = []
          self.quadTree.retriveAll(objects)
          for x in range(len(objects)):
              obj = []
              self.quadTree.findObjects(obj, objects[x])
              for y in range(len(obj)):
                  objects[x].getCollisionModel().intersect(obj[y].getCollisionModel())
              del obj[:]
          del objects[:]
  
      def addObject(self, p_object):
          self.quadTree.insert(p_object)
          self.pObjects.append(p_object)
  
      def getObject(self, index):
          return self.pObjects[index]
  
      def getLength(self):
          return len(self.pObjects)
  
subject: Change multi line string to be regular comment.