code: def __init__(self, x, y):
      self._x = x
      self._y = y
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import pytest
  import numpy
  import torch
  import torch.nn
  import torch.optim
  from torch.utils.data import Dataset, DataLoader
  import bluefog.torch
  from bluefog.common import topology_util
label_desc: Use image node_id 1 to create a new SimpleDataset object  with example: obj = SimpleDataset(x, y)