code: def brightness_multi(x, gamma=1, gain=1, is_random=False):
      
      if is_random:
          gamma = np.random.uniform(1 - gamma, 1 + gamma)
  
      results = []
      for data in x:
          results.append(exposure.adjust_gamma(data, gamma, gain))
      return np.asarray(results)
docs: Change the brightness of multiply images, randomly or non-randomly.
      Usually be used for image segmentation which x=[X, Y], X and Y should be matched.
  
      Parameters
      -----------
      x : list of numpyarray
          List of images with dimension of [n_images, row, col, channel] (default).
      others : args
          See ``tl.prepro.brightness``.
  
      Returns
      -------
      numpy.array
          A list of processed images.