class_docstr: A dataset that combines multiple dataset-like objects, e.g.
  Datasets, lists, arrays, etc.
  
  The i-th sample is defined as `(x1[i], x2[i], ...)`.
  
  Parameters
  ----------
  *args : one or more dataset-like objects
      The data arrays.
code: def __len__(self):
      return self._length
  
imports: import os
  from ...None import recordio, ndarray
  from ...util import default_array
label_desc: Use image node_id 3 for calling the ArrayDataset obj's underlying member method code with example usage: obj.__len__() and returns: self