code: def _build_model(self):
      self.model = Graph2Seq.load_checkpoint(
          os.path.join("examples/pytorch/nmt/save", opt["name"]),
          "best.pth",
      ).to(self.device)
  
imports: import os
  import resource
  import numpy
  import torch
  from torch.utils.data import DataLoader
  from torch.utils.tensorboard import SummaryWriter
  from graph4nlp.pytorch.models.graph2seq import Graph2Seq
  from graph4nlp.pytorch.modules.evaluation import BLEU
  from args import get_args
  from dataset import IWSLT14Dataset
  from utils import get_log, wordid2str
label_desc: Use image node_id 5 for calling the NMT obj's underlying member method code with example usage: obj._build_model() without return types