class_docstr: Preprocess screen images from Atari 2600 games.
  
  The image is represented by an array of shape (210, 160, 3). See
  https://storage.googleapis.com/deepmind-media/dqn/DQNNaturePaper.pdf
  for more details.
class_docstr_tok: ["Preprocess","screen","images","from","Atari","2600","games",".","The","image","is","represented","by","an","array","of","shape","(","210",",","160",",","3",")",".","See","https",":","\/\/storage.googleapis.com\/deepmind-media\/dqn\/DQNNaturePaper.pdf","for","more","details","."]
docstr: Return shape of preprocessed Atari images.
docstr_tok: ["Return","shape","of","preprocessed","Atari","images","."]
code: def output_shape(self):
      """Return shape of preprocessed Atari images."""
      return (self.__history_len, 84, 84)
  
imports: from abc import ABCMeta, abstractmethod
  from collections import deque
  import numpy
  from PIL import Image
label_desc: Use image node_id 2 for calling the AtariPreprocessing obj's underlying member method code with example usage: obj.output_shape() and returns: self,  int,  int