code: def __getitem__(self, idx):
      if len(self._data) == 1:
          return self._data[idx][0]
      else:
          return tuple(data[:, idx] for data in self._data)
  
imports: import os
  import logging
  import sys
  import re
  import mxnet
  from common import TemporaryDirectory
  from mxnet import np
  from mxnet.gluon import nn, loss
  from mxnet.gluon.contrib.estimator import estimator, event_handler
  from mxnet.gluon.contrib.estimator.event_handler import LoggingHandler
  from mxnet.gluon.contrib.estimator.event_handler import ValidationHandler
  from mxnet.gluon.contrib.estimator import EpochEnd
  from mxnet.gluon.data.dataset import Dataset
label_desc: Use image node_id 2 for calling the AxisArrayDataset obj's underlying member method code with example usage: obj.__getitem__(idx) and returns: self, tuple