code: def save(model, epoch, save_dir, file_name):
      file_name = "epoch_" + str(epoch) + "__" + file_name
      save_path = os.path.join(save_dir, file_name)
      torch.save(model.state_dict(), save_path)
  
file_path: vision/references/similarity/train.py
imports: import os
  import torch
  import torchvision.transforms
  from loss import TripletMarginLoss
  from model import EmbeddingNet
  from sampler import PKSampler
  from torch.optim import Adam
  from torch.utils.data import DataLoader
  from torchvision.datasets import FashionMNIST
label_desc: Use image node_id 4 for calling a global function with example usage: save(model, epoch, save_dir, file_name) without return types