class_docstr: y = a * x + b
class_docstr_tok: ["y","=","a","*","x","+","b"]
code: def __getitem__(self, index):
      return self.x[index, None], self.y[index, None]
  
file_path: BigDL/python/orca/example/learn/horovod/pytorch_estimator.py
imports: import argparse
  import numpy
  import torch
  import torch.nn
  from bigdl.orca import init_orca_context, stop_orca_context
  from bigdl.orca.learn.pytorch import Estimator
label_desc: Use image node_id 2 for calling the LinearDataset obj's underlying member method code with example usage: obj.__getitem__(index) and returns: self,  self