code: def get_x(self, test_type):
      if test_type == "list":
          return [
              chainer.Variable(np.array(3, dtype=np.float32)),
              chainer.Variable(np.array(5, dtype=np.float32)),
          ]
      elif test_type == "dict":
          return {"x": chainer.Variable(np.array(3, dtype=np.float32))}
      elif test_type == "array":
          return np.array(3, dtype=np.float32)
      else:
          assert test_type == "variable"
          return chainer.Variable(np.array(3, dtype=np.float32))
  
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 TestRetainInputHook obj's underlying member method code with example usage: obj.get_x(test_type) and returns: list, dict, np, chainer