code: def test_multi_device(self):
      devices = ("cuda:1", "cuda:0")
      for current_dev, tensor_dev in product(devices, devices):
          with torch.cuda.device(current_dev):
              torch.cuda.synchronize()
              self.gen_single_type_test(
                  param_type=torch.float, device=tensor_dev
              )
  
file_path: apex/tests/L0/run_optimizers/test_fused_novograd.py
imports: import torch
  from torch.optim import Optimizer
  import math
  import apex
  import unittest
  from test_fused_optimizer import TestFusedOptimizer
  from itertools import product
label_desc: Use image node_id 4 for calling the TestFusedNovoGrad obj's underlying member method code with example usage: obj.test_multi_device() without return types