code: def test_python_add2_forward_backward(seed):
      from nbla_test_utils import function_tester
  
      rng = np.random.RandomState(seed)
      inputs = [
          rng.randn(2, 3, 4).astype(np.float32) * 2 for _ in range(2)
      ]
      add2 = Add2()
      function_tester(
          rng, add2, lambda x, y: x + y, inputs, atol_b=2e-3
      )
  
file_path: nnabla/python/test/test_python_function.py
imports: import pytest
  import numpy
  import nnabla.functions
  import nnabla
  from nnabla.function import PythonFunction
label_desc: Use image node_id 1 for calling a global function with example usage: test_python_add2_forward_backward(seed) without return types