code: def forward(self, enc_graph, dec_graph, ufeat, ifeat):
      user_out, movie_out = self.encoder(enc_graph, ufeat, ifeat)
      pred_ratings = self.decoder(dec_graph, user_out, movie_out)
      return pred_ratings
  
file_path: dgl/examples/pytorch/gcmc/train.py
imports: import argparse
  import logging
  import os
  import random
  import string
  import time
  import numpy
  import torch
  import torch.nn
  from data import MovieLens
  from model import BiDecoder, GCMCLayer
  from utils import get_activation, get_optimizer, MetricLogger, torch_net_info, torch_total_param_num
label_desc: Use image node_id 2 for calling the Net obj's underlying member method code with example usage: obj.forward(enc_graph, dec_graph, ufeat, ifeat) and returns: pred_ratings