code: def test_if_no_best_weights_on_train_end_raise_warnings(self):
      model_restore = BestModelRestore(monitor="val_loss")
      a_log = {}
  
      with self.assertWarns(UserWarning):
          model_restore.on_train_end(a_log)
  
file_path: poutyne/tests/framework/callbacks/test_best_model_restore.py
imports: import unittest
  from unittest import TestCase
  import torch
  import torch.nn
  from poutyne import BestModelRestore, Model, torch_to_numpy
  from tests.framework.tools import some_data_generator
label_desc: Use image node_id 6 for calling the BestModelRestoreTest obj's underlying member method code with example usage: obj.test_if_no_best_weights_on_train_end_raise_warnings() without return types