code: def test_forward_backward(N, C, H, W, params, seed, ctx, func_name):
      rng = np.random.RandomState(seed)
      x1 = rng.randn(N, H, W, C).astype(np.float32)
      x2 = rng.randn(N, H, W, C).astype(np.float32)
      # must use function_bases.patch_correlation for func_name check in tester
      function_tester(
          rng,
          nn.function_bases.patch_correlation,
          patch_correlation,
          [x1, x2],
          func_kwargs=params,
          func_name=func_name,
          ctx=ctx,
          atol_b=2e-2,
      )
  
file_path: nnabla/python/test/function/test_patch_correlation.py
imports: import pytest
  import numpy
  import nnabla
  import nnabla.functions
  from nbla_test_utils import list_context, function_tester
label_desc: Use image node_id 4 for calling a global function with example usage: test_forward_backward(N, C, H, W, params, seed, ctx, func_name) without return types