code: def difference(self, previous_game_frame):
      current = skimage.filters.gaussian(self.grayscale_frame, 8)
      previous = skimage.filters.gaussian(
          previous_game_frame.grayscale_frame, 8
      )
  
      return current - previous
  
imports: import skimage.color
  import skimage.measure
  import skimage.transform
  import skimage.filters
  import skimage.morphology
  import numpy
  import io
  from PIL import Image
label_desc: Use image node_id 11 for calling the GameFrame obj's underlying member method code with example usage: obj.difference(previous_game_frame) and returns: unknown