input: Write a Python function to initialize the game of Pong and set up the game loop.
  assert isinstance(init_pong_game(), pygame.Surface)  # Ensure the function returns a pygame Surface object
  assert init_pong_game().get_width() == 600  # Ensure the game screen has the correct width
  assert init_pong_game().get_height() == 400  # Ensure the game screen has the correct height
output: def init_pong_game():
      import pygame
      import sys
  
      # Initialize Pygame
      pygame.init()
  
      # Set up the game screen
      screen_width = 600
      screen_height = 400
      screen = pygame.display.set_mode((screen_width, screen_height))
      pygame.display.set_caption('Pong Game')
  
      # Set up the game clock
      clock = pygame.time.Clock()
  
      # Main game loop
      running = True
      while running:
          for event in pygame.event.get():
              if event.type == pygame.QUIT:
                  running = False
  
          # Fill the screen with black color
          screen.fill((0, 0, 0))
  
          # Update the display
          pygame.display.flip()
  
          # Cap the frame rate
          clock.tick(60)
  
      pygame.quit()
      sys.exit()
  
      return screen