Just downloaded the jupyter notebook for deep Q-learning and I would get error for the code block that is suppose to extract and process the rendered images from the environment.
---------------------------------------------------------------------------
NotImplementedError                       Traceback (most recent call last)
<ipython-input-7-db314a5502f8> in <module>()
     39 env.reset()
     40 plt.figure()
---> 41 plt.imshow(get_screen().cpu().squeeze(0).permute(1, 2, 0).numpy(),
     42            interpolation='none')
     43 plt.title('Example extracted screen')

<ipython-input-7-db314a5502f8> in get_screen()
     14 
     15 def get_screen():
---> 16     screen = env.render(mode='rgb_array').transpose(
     17         (2, 0, 1))  # transpose into torch order (CHW)
     18     # Strip off the top and bottom of the screen

C:\Anaconda3\lib\site-packages\gym\envs\classic_control\cartpole.py in render(self, mode)
    105         if self.viewer is None:
    106             from gym.envs.classic_control import rendering
--> 107             self.viewer = rendering.Viewer(screen_width, screen_height)
    108             l,r,t,b = -cartwidth/2, cartwidth/2, cartheight/2, -cartheight/2
    109             axleoffset =cartheight/4.0

C:\Anaconda3\lib\site-packages\gym\envs\classic_control\rendering.py in __init__(self, width, height, display)
     49         self.width = width
     50         self.height = height
---> 51         self.window = pyglet.window.Window(width=width, height=height, display=display)
     52         self.window.on_close = self.window_closed_by_user
     53         self.isopen = True

C:\Anaconda3\lib\site-packages\pyglet\window\__init__.py in __init__(self, width, height, caption, resizable, style, fullscreen, visible, vsync, display, screen, config, context, mode)
    502 
    503         if not screen:
--> 504             screen = display.get_default_screen()
    505 
    506         if not config:

C:\Anaconda3\lib\site-packages\pyglet\canvas\base.py in get_default_screen(self)
     71         :rtype: :class:`Screen`
     72         '''
---> 73         return self.get_screens()[0]
     74 
     75     def get_windows(self):

C:\Anaconda3\lib\site-packages\pyglet\canvas\base.py in get_screens(self)
     63         :rtype: list of :class:`Screen`
     64         '''
---> 65         raise NotImplementedError('abstract')
     66 
     67     def get_default_screen(self):

NotImplementedError: abstract

<matplotlib.figure.Figure at 0x202fd020278>

I am not sure what I need to do can some one please help?
Link to the tutorial where you can download the notebook.
https://pytorch.org/tutorials/intermediate/reinforcement_q_learning.html#sphx-glr-download-intermediate-reinforcement-q-learning-py 4