code: def test_unlink_forward_backward(seed, shape, ctx, func_name):
      rng = np.random.RandomState(seed)
      x0 = rng.randn(*(shape)).astype(np.float32)
      ref = ref_unlink(x0)
  
      x = nn.Variable(shape)
      y = F.unlink(x)
      x.d = x0
      x.grad.zero()
      y.forward()
      y.backward()
      res = y.d
  
      atol_f = 1e-6
      assert_allclose(ref, res, atol=atol_f)
  
      atol_b = 1e-6
      ref = np.zeros(shape)
      res = x.g
      assert_allclose(ref, res, atol=atol_b)
  
file_path: nnabla/python/test/function/test_unlink.py
imports: import pytest
  import numpy
  import nnabla
  import nnabla.functions
  from nbla_test_utils import list_context
  from nnabla.testing import assert_allclose
label_desc: Use image node_id 2 for calling a global function with example usage: test_unlink_forward_backward(seed, shape, ctx, func_name) without return types