code: def setUp(self):
      class Model(chainer.Chain):
          def __call__(self, x, gamma, beta, mean, var):
              return F.fixed_batch_normalization(
                  x, gamma, beta, mean, var
              )
  
      self.model = Model()
      self.x = input_generator.increasing(2, 5)
      self.mean = self.x.mean(axis=0)
      self.var = self.x.var(axis=0)
      self.gamma = np.ones_like(self.mean, dtype=self.x.dtype)
      self.beta = np.zeros_like(self.mean, dtype=self.x.dtype)
  
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 1 for calling the TestFixedBatchNormalizationFunctionExplicitInputs obj's underlying member method code with example usage: obj.setUp() and returns: F