code: def forward_expected(self, inputs):
      (x,) = inputs
      groups = self.groups
      mean = _calc_mean(x, groups)
      projection = _calc_projection(x, mean, self.eps, groups)
      return (
          _decorrelated_batch_normalization(
              x, mean, projection, groups
          ),
      )
  
imports: import numpy
  from chainer import functions
  from chainer import testing
label_desc: Use image node_id 4 for calling the TestDecorrelatedBatchNormalization obj's underlying member method code with example usage: obj.forward_expected(inputs) and returns: _decorrelated_batch_normalization