code: def MessagePassing(gw, feature, num_layers, norm=None):
      """Precomputing message passing."""
  
      def send_src_copy(src_feat, dst_feat, edge_feat):
          """send_src_copy"""
          return src_feat["h"]
  
      for _ in range(num_layers):
          if norm is not None:
              feature = feature * norm
  
          msg = gw.send(send_src_copy, nfeat_list=[("h", feature)])
  
          feature = gw.recv(msg, "sum")
  
          if norm is not None:
              feature = feature * norm
  
      return feature
  
file_path: PGL/legacy/examples/sgc/sgc.py
imports: import os
  import argparse
  import numpy
  import random
  import time
  import pgl
  from pgl import data_loader
  from pgl.utils.logger import log
  from pgl.utils import paddle_helper
  import paddle.fluid
label_desc: Use image node_id 3 for calling a global function with example usage: MessagePassing(gw, feature, num_layers, norm) and returns: feature, src_feat