old_contents: import pygame
  import random
  import imghdr
  import logging
  import os
  
  class BackgroundLevel(pygame.sprite.Sprite):
  
      def __init__(self, path):
          if(sys.version_info > (3, 0)):
  	        super().__init__()
          else:
  	        super(BackgroundLevel, self).__init__()
  
          self.__levels = []
  
          levelDir = os.listdir(path)
  
          for file in levelDir:
              isImageFile = self.__checkIfImageFile(path + file)
  
              if isImageFile:
                  self.__levels.append(file)
  
          self.__totalLevels = len(self.__levels)
          random.shuffle(self.__levels)
  
      def __checkIfImageFile(self, imageFile):
          isFile = os.path.isfile(imageFile)
          
          if isFile:
              isImageFile = imghdr.what(imageFile)
              if isImageFile is not None:
                  return True
  
          return False
  
      def loadLevel(self, path, level):
          file = os.path.abspath(path + self.__levels[level])
          
          try:
              self.image = pygame.image.load(file).convert()
          except pygame.error as errorMessage:
              logging.exception(errorMessage)
              raise
  
          self.rect = self.image.get_rect()
  
      def finishedAllLevels(self, currentLevel):
          if currentLevel == self.__totalLevels - 1:
              return True
          
          return False
  
new_contents: import pygame
  import random
  import imghdr
  import logging
  import sys
  import os
  
  class BackgroundLevel(pygame.sprite.Sprite):
  
      def __init__(self, path):
          if(sys.version_info > (3, 0)):
  	        super().__init__()
          else:
  	        super(BackgroundLevel, self).__init__()
  
          self.__levels = []
  
          levelDir = os.listdir(path)
  
          for file in levelDir:
              isImageFile = self.__checkIfImageFile(path + file)
  
              if isImageFile:
                  self.__levels.append(file)
  
          self.__totalLevels = len(self.__levels)
          random.shuffle(self.__levels)
  
      def __checkIfImageFile(self, imageFile):
          isFile = os.path.isfile(imageFile)
          
          if isFile:
              isImageFile = imghdr.what(imageFile)
              if isImageFile is not None:
                  return True
  
          return False
  
      def loadLevel(self, path, level):
          file = os.path.abspath(path + self.__levels[level])
          
          try:
              self.image = pygame.image.load(file).convert()
          except pygame.error as errorMessage:
              logging.exception(errorMessage)
              raise
  
          self.rect = self.image.get_rect()
  
      def finishedAllLevels(self, currentLevel):
          if currentLevel == self.__totalLevels - 1:
              return True
          
          return False
  
subject: Update level.py