code: def test_celu_forward_backward(seed, alpha, axis, ctx, func_name):
      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.celu,
          ref_celu,
          inputs,
          func_args=[alpha, axis],
          ctx=ctx,
          func_name=func_name,
          atol_b=4e-3,
      )
  
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_celu_forward_backward(seed, alpha, axis, ctx, func_name) without return types