def get_base(self):
        for script in self._revision_map.values():
            if script and script.down_revision is None \
                and script.revision in self._revision_map:
                return script.revision
        else:
            return None
`Auth` requesting protected resource by logined user
dataset/ETHPy150Open goFrendiAsgard/kokoropy/kokoropy/packages/alembic/script.py/ScriptDirectory.get_base--crossover with--dataset/ETHPy150Open SmartTeleMax/iktomi/tests/auth.py/CookieAuthTests.test_protected_resource