code: def __len__(self):
      if self._indices is None:
          return len(self._dataset)
      elif isinstance(self._indices, slice):
          start, stop, step = self._indices.indices(len(self._dataset))
          return len(six.moves.range(start, stop, step))
      else:
          return len(self._indices)
  
imports: import numbers
  import numpy
  import six
  from chainer.dataset.tabular import tabular_dataset
label_desc: Use image node_id 2 for calling the _Slice obj's underlying member method code with example usage: obj.__len__() and returns: len, len, len