code: def running_var(self):
      self._warn_accessing_property()
      return self._running_var
  
imports: import warnings
  import numpy
  from chainer import backend
  from chainer.backends import cuda
  from chainer import configuration
  from chainer import function
  from chainer.functions.normalization import batch_normalization
  from chainer.utils import type_check
label_desc: Use image node_id 4 for calling the BatchRenormalizationFunction obj's underlying member method code with example usage: obj.running_var() and returns: self