class_docstr: Mock internal ALE for testing.
code: def getScreenGrayscale(self, screen):  # pylint: disable=invalid-name
      screen.fill(self.screen_value)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from gym import core
  import numpy
  import tensorflow
  from tf_agents.environments import atari_preprocessing
label_desc: Use image node_id 3 for calling the MockALE obj's underlying member method code with example usage: obj.getScreenGrayscale(screen) without return types