code: def _warn_old_model():
      msg = (
          "Found moving statistics of old DecorrelatedBatchNormalization, whose "
          "algorithm was different from the paper."
      )
      warnings.warn(msg)
  
imports: import functools
  import warnings
  import numpy
  import chainer
  from chainer import configuration
  from chainer import functions
  from chainer import link
  import chainer.serializer
  from chainer.utils import argument
label_desc: Use image node_id 1 for calling a global function with example usage: _warn_old_model() without return types