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
from tests.test_utils.config import conf_vars
from tests.test_utils.reset_warning_registry import reset_warning_registry
@unittest.mock.patch.dict(
    'os.environ',
    {
        'AIRFLOW__TESTSECTION__TESTKEY': 'testvalue',
        'AIRFLOW__TESTSECTION__TESTPERCENT': 'with%percent',
        'AIRFLOW__TESTCMDENV__ITSACOMMAND_CMD': 'echo -n "OK"',
        'AIRFLOW__TESTCMDENV__NOTACOMMAND_CMD': 'echo -n "NOT OK"',
    },
)
class TestConf(unittest.TestCase):
    def test_airflow_home_default(self):
        with unittest.mock.patch.dict('os.environ'):
            if 'AIRFLOW_HOME' in os.environ:
                del os.environ['AIRFLOW_HOME']
            assert get_airflow_home() == expand_env_var('~/airflow')
    def test_airflow_home_override(self):
        with unittest.mock.patch.dict('os.environ', AIRFLOW_HOME='/path/to/airflow'):
            assert get_airflow_home() == '/path/to/airflow'
    def test_airflow_config_default(self):
        with unittest.mock.patch.dict('os.environ'):
            if 'AIRFLOW_CONFIG' in os.environ:
                del os.environ['AIRFLOW_CONFIG']
            assert get_airflow_config('/home/airflow') == expand_env_var('/home/airflow/airflow.cfg')
    def test_airflow_config_override(self):
        with unittest.mock.patch.dict('os.environ', AIRFLOW_CONFIG='/path/to/airflow/airflow.cfg'):
            assert get_airflow_config('/home//airflow') == '/path/to/airflow/airflow.cfg'
    @conf_vars({("core", "percent"): "with%%inside"})
    def test_case_sensitivity(self):