code: def num_parameters(self):
      return self._num_parameters
  
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 3 for calling the LinearNet obj's underlying member method code with example usage: obj.num_parameters() and returns: self