class_docstr: decode image 
class_docstr_tok: ["decode","image"]
code: def __call__(self, img):
      if six.PY2:
          assert (
              type(img) is str and len(img) > 0
          ), "invalid input 'img' in DecodeImage"
      else:
          assert (
              type(img) is bytes and len(img) > 0
          ), "invalid input 'img' in DecodeImage"
      data = np.frombuffer(img, dtype="uint8")
      img = cv2.imdecode(data, 1)
      if self.to_rgb:
          assert img.shape[2] == 3, "invalid shape of image[%s]" % (
              img.shape
          )
          img = img[:, :, ::-1]
  
      if self.channel_first:
          img = img.transpose((2, 0, 1))
  
      return img
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import base64
  import inspect
  import math
  import os
  import random
  import sys
  from functools import partial
  import cv2
  import numpy
  import paddle
  import paddle.nn.functional
  import six
  from paddle.vision.transforms import ColorJitter
  from PIL import Image
label_desc: Use image node_id 2 for calling the DecodeImage obj's underlying member method code with example usage: obj.__call__(img) and returns: img