code: def test_outputs(self):
      class MLP(chainer.Chain):
          def __init__(self, n_units, n_out):
              super(MLP, self).__init__()
              with self.init_scope():
                  self.l1 = L.Linear(None, n_units)
                  self.l2 = L.Linear(None, n_units)
                  self.l3 = L.Linear(None, n_out)
  
          def __call__(self, x):
              h1 = F.relu(self.l1(x))
              # Unused for some reason, then params are not initialized.
              # h2 = F.relu(self.l2(h1))
              return self.l3(h1)
  
      model = MLP(100, 10)
      x = np.random.rand(1, 768).astype(np.float32)
  
      with testing.assert_warns(UserWarning):
          self.expect(model, x)
  
imports: import unittest
  import chainer
  import chainer.functions
  import chainer.links
  from chainer import testing
  import numpy
  import pytest
  from onnx_chainer import export
  from onnx_chainer.export import RetainInputHook
  from onnx_chainer.testing import input_generator
  from onnx_chainer_tests.helper import ONNXModelTest
label_desc: Use image node_id 1 for calling the TestUnusedLink obj's underlying member method code with example usage: obj.test_outputs() and returns: self