code: def test_save(self):
      self.art_model.save(filename="test.file", path=None)
      self.art_model.save(filename="test.file", path="./")
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import logging
  import unittest
  import numpy
  from art.estimators.regression.keras import KerasRegressor
  from tests.utils import TestBase, master_seed, get_tabular_regressor_kr
label_desc: Use image node_id 4 for calling the TestKerasRegressorClass obj's underlying member method code with example usage: obj.test_save() without return types