code: def test_backprop_double_backprop(method):
      shape = (1,)
      dtype = chainerx.float32
  
      xs = (
          chainerx.full(shape, 2, dtype).require_grad(),
          chainerx.full(shape, 3, dtype),
      )
      expected_gxs = (
          chainerx.full(shape, 2, dtype),
          None,
      )
  
      def fprop(x0, x1):
          assert x0.is_grad_required()
  
          h = x0 * (x0 + x1)
          chainerx.backward(h, enable_double_backprop=True)
          gx0 = x0.get_grad()
          x0.cleargrad()
          return (gx0,)
  
      _check_backprop(method, fprop, xs, expected_gxs)
  
imports: import chainerx
  import pytest
label_desc: Use image node_id 12 for calling a global function with example usage: test_backprop_double_backprop(method) and returns: gx0