code: def test_output(self):
      def test_input_names(onnx_model, path):
          initializer_names = get_initializer_names(onnx_model)
          assert len(initializer_names) == 4
          assert (
              "BatchNormalization_0_param_avg_mean" in initializer_names
          )
          assert (
              "BatchNormalization_0_param_avg_var" in initializer_names
          )
  
      self.expect(
          self.model, self.x, custom_model_test_func=test_input_names
      )
  
imports: import chainer
  import chainer.functions
  import chainer.links
  from chainer import testing
  import numpy
  from onnx_chainer.testing import input_generator
  from onnx_chainer_tests.helper import get_initializer_names
  from onnx_chainer_tests.helper import ONNXModelTest
label_desc: Use image node_id 2 for calling the TestBatchNormalizationFunction obj's underlying member method code with example usage: obj.test_output() without return types