code: def frame(I=None, second=5, saveable=True, name='frame', cmap=None, fig_idx=12836):
      
      import matplotlib.pyplot as plt
      if saveable is False:
          plt.ion()
      plt.figure(fig_idx)  # show all feature images
  
      if len(I.shape) and I.shape[-1] == 1:  # (10,10,1) --> (10,10)
          I = I[:, :, 0]
  
      plt.imshow(I, cmap)
      plt.title(name)
      # plt.gca().xaxis.set_major_locator(plt.NullLocator())    # distable tick
      # plt.gca().yaxis.set_major_locator(plt.NullLocator())
  
      if saveable:
          plt.savefig(name + '.pdf', format='pdf')
      else:
          plt.draw()
          plt.pause(second)
docs: Display a frame. Make sure OpenAI Gym render() is disable before using it.
  
      Parameters
      ----------
      I : numpy.array
          The image.
      second : int
          The display second(s) for the image(s), if saveable is False.
      saveable : boolean
          Save or plot the figure.
      name : str
          A name to save the image, if saveable is True.
      cmap : None or str
          'gray' for greyscale, None for default, etc.
      fig_idx : int
          matplotlib figure index.
  
      Examples
      --------
      >>> env = gym.make("Pong-v0")
      >>> observation = env.reset()
      >>> tl.visualize.frame(observation)