class_docstr: Calculate color map for mapping segmentation result.
code: def __init__(self, num_classes: int = 256):
      self.num_classes = num_classes + 1
  
imports: import os
  import random
  from typing import Callable, Union, List, Tuple
  import cv2
  import numpy
  from PIL import Image
  import paddlehub.vision.functional
label_desc: Use image node_id 1 to create a new ColorMap object  with example: obj = ColorMap(num_classes)