https://airflow.apache.org/docs/apache-airflow/stable/configurations-ref.html#store-dag-code

![Captura de pantalla 2021-05-26 a las 17 47 56](https://user-images.githubusercontent.com/11339132/119691160-a2049a00-be4a-11eb-8f55-0ad2c6117620.png)

The Default is True or None?
tests/core/test_configuration.py
with pytest.warns(FutureWarning):
            with unittest.mock.patch.dict('os.environ', AIRFLOW__CORE__HOSTNAME_CALLABLE='socket:getfqdn'):
                test_conf = make_config()
                assert test_conf.get('core', 'hostname_callable') == 'socket.getfqdn'
        with reset_warning_registry():
            with warnings.catch_warnings(record=True) as warning:
                with unittest.mock.patch.dict(
                    'os.environ',
                    AIRFLOW__CORE__HOSTNAME_CALLABLE='CarrierPigeon',
                ):
                    test_conf = make_config()
                    assert test_conf.get('core', 'hostname_callable') == 'CarrierPigeon'
                    assert [] == warning
    def test_deprecated_funcs(self):
        for func in [
            'load_test_config',
            'get',
            'getboolean',
            'getfloat',
            'getint',
            'has_option',
            'remove_option',
            'as_dict',
            'set',
        ]:
            with mock.patch(f'airflow.configuration.conf.{func}') as mock_method:
                with pytest.warns(DeprecationWarning):
                    getattr(configuration, func)()
                mock_method.assert_called_once()
    def test_command_from_env(self):