code: def test_multi_device(self):
      devices = ("cuda:0", "cuda:1")
      for current_dev, tensor_dev in product(devices, devices):
          with torch.cuda.device(current_dev):
              self.gen_single_type_test(
                  param_type=torch.float, device=tensor_dev
              )
  
imports: import unittest
  import os
  import torch
  from torch.optim import Optimizer
  import apex
  from apex.multi_tensor_apply import multi_tensor_applier
  from itertools import product
label_desc: Use image node_id 5 for calling the TestFusedMixedPrecisionLamb obj's underlying member method code with example usage: obj.test_multi_device() without return types