code: def test_reduce_forward_backward(seed, ctx, func_name, op):
      from nbla_test_utils import function_tester
  
      rng = np.random.RandomState(seed)
      inputs = [rng.randn(2, 3, 4).astype(np.float32) * 2]
      function_tester(
          rng, F.reduce, ref_reduce, inputs, func_args=[op], ctx=ctx
      )
  
imports: import pytest
  import numpy
  import nnabla.functions
  from nbla_test_utils import list_context
label_desc: Use image node_id 2 for calling a global function with example usage: test_reduce_forward_backward(seed, ctx, func_name, op) without return types