class_docstr: Base class for defining preprocessing.
  
  All subclass constructors will take input_shape as the first argument.
class_docstr_tok: ["Base","class","for","defining","preprocessing",".","All","subclass","constructors","will","take","input_shape","as","the","first","argument","."]
docstr: Return shape of preprocessed observation.
docstr_tok: ["Return","shape","of","preprocessed","observation","."]
code: def output_shape(self):
      """Return shape of preprocessed observation."""
      pass
  
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 Preprocessing obj's underlying member method code with example usage: obj.output_shape() without return types