def METHOD_NAME(self):
    """Test functionality of copy_update in utility_functions.py."""
    self.assertEqual(utility_functions.copy_update({'a': 1}, {}), {'a': 1})
    self.assertEqual(utility_functions.copy_update({'a': 1}, {'b': 2}), {
        'a': 1,
        'b': 2
    })
    self.assertEqual(utility_functions.copy_update({'a': 1}, {'a': 2}),
                     {'a': 2})