class_docstr: y = a * x + b
code: def __init__(self, a, b, size=1000):
      x = np.arange(0, 10, 10 / size, dtype=np.float32)
      self.x = torch.from_numpy(x)
      self.y = torch.from_numpy(a * x + b)
  
imports: from bigdl.orca.learn.pytorch import Estimator
  from unittest import TestCase
  import pytest
  import torch
  import torch.nn
  import os
  import numpy
  from tempfile import TemporaryDirectory
label_desc: Use image node_id 1 to create a new LinearDataset object from inherited base classes: torch.utils.data with example: obj = LinearDataset(a, b, size)