code: def test_csis_validation_batch():
      pyro.clear_param_store()
      guide = Guide()
      csis = pyro.infer.CSIS(
          model, guide, pyro.optim.Adam({}), validation_batch_size=5
      )
      init_loss_1 = csis.validation_loss()
      init_loss_2 = csis.validation_loss()
      csis.step()
      next_loss = csis.validation_loss()
      assert_equal(init_loss_1, init_loss_2)
      assert_not_equal(init_loss_1, next_loss)
  
file_path: pyro/tests/infer/test_csis.py
imports: import pytest
  import torch
  import torch.nn
  import pyro
  import pyro.distributions
  import pyro.infer
  import pyro.optim
  from tests.common import assert_equal, assert_not_equal
label_desc: Use image node_id 4 for calling a global function with example usage: test_csis_validation_batch() without return types