code: def mode(self):
      if self._unary is None:
          return self._dataset.mode
      elif self._unary:
          return None
      else:
          return self._dataset.mode or tuple
  
imports: import numbers
  import numpy
  import six
  from chainer.dataset.tabular import tabular_dataset
label_desc: Use image node_id 4 for calling the _Slice obj's underlying member method code with example usage: obj.mode() and returns: self, None, unknown