code: def test_hard_sigmoid_forward_backward(seed, ctx, func_name):
      from nbla_test_utils import cap_ignore_region, function_tester
  
      rng = np.random.RandomState(seed)
      inputs = [
          np.clip(
              np.abs(rng.randn(2, 3, 4).astype(np.float32)) * 1e4,
              1e-2,
              1e4,
          )
      ]
      function_tester(
          rng,
          F.hard_sigmoid,
          ref_hard_sigmoid,
          inputs,
          ctx=ctx,
          func_name=func_name,
          ref_grad=ref_hard_sigmoid_backward,
      )
  
file_path: nnabla/python/test/function/test_hard_sigmoid.py
imports: import pytest
  import numpy
  import nnabla.functions
  from nbla_test_utils import list_context
label_desc: Use image node_id 3 for calling a global function with example usage: test_hard_sigmoid_forward_backward(seed, ctx, func_name) without return types