code: def setUp(self):
      torch.manual_seed(42)
      self.pytorch_network = nn.Linear(1, 1)
      self.loss_function = nn.MSELoss()
      self.optimizer = torch.optim.SGD(
          self.pytorch_network.parameters(), lr=1e-3
      )
      self.model = Model(
          self.pytorch_network, self.optimizer, self.loss_function
      )
      self.temp_dir_obj = TemporaryDirectory()
      self.checkpoint_filename = os.path.join(
          self.temp_dir_obj.name, "my_checkpoint_{epoch}.ckpt"
      )
  
imports: import os
  import unittest
  from tempfile import TemporaryDirectory
  from unittest import TestCase
  import torch
  import torch.nn
  from poutyne import Model, ModelCheckpoint, torch_to_numpy
  from tests.framework.tools import some_data_generator
label_desc: Use image node_id 1 for calling the ModelCheckpointTest obj's underlying member method code with example usage: obj.setUp() without return types