code: def init_op(self):
      self.seq = Compose(
          [
              NormalizeImage(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5]),
              ToCHW(),
          ]
      )
  
imports: import io
  import os
  import sys
  import base64
  import argparse
  import yaml
  import numpy
  from PIL import Image
  from paddle_serving_server.web_service import WebService, Op
  from preprocess_ops import ResizeImage, CenterCropImage, NormalizeImage, ToCHW, Compose
label_desc: Use image node_id 1 for calling the SegOp obj's underlying member method code with example usage: obj.init_op() without return types