class_docstr: Compose several preprocess together.
  Args:
      preprocess (list of ``Preprocess`` objects): list of preprocess to compose.
code: def __call__(self, img):
      for t in self.preprocess:
          img = t(img)
      return img
  
imports: import random
  import cv2
  import numpy
  import torch
  from scipy import signal
label_desc: Use image node_id 2 for calling the Compose obj's underlying member method code with example usage: obj.__call__(img) and returns: img