How to use the aldjemy.core.Cache function in aldjemy

def test_engines_cache(self):
        from aldjemy.core import Cache, get_engine

        self.assertEqual(get_engine('default'), Cache.engines['default'])
        self.assertEqual(get_engine('logs'), Cache.engines['logs'])
        self.assertEqual(get_engine(), Cache.engines['default'])
        self.assertNotEqual(get_engine('default'), get_engine('logs'))

def test_engines_cache(self):
        from aldjemy.core import Cache, get_engine

        self.assertEqual(get_engine('default'), Cache.engines['default'])
        self.assertEqual(get_engine('logs'), Cache.engines['logs'])
        self.assertEqual(get_engine(), Cache.engines['default'])
        self.assertNotEqual(get_engine('default'), get_engine('logs'))

def get_engine(alias='default'):
    if alias not in Cache.engines:
        engine_string = get_engine_string(alias)
        # we have to use autocommit=True, because SQLAlchemy
        # is not aware of Django transactions
        kw = {}
        if engine_string == 'sqlite3':
            kw['native_datetime'] = True

        pool = DjangoPool(alias=alias, creator=None)
        Cache.engines[alias] = create_engine(get_connection_string(alias),
                                             pool=pool, **kw)
    return Cache.engines[alias]

def prepare_models():

    tables = get_tables()
    models = get_django_models()

    sa_models_by_django_models = getattr(Cache, 'sa_models', {})

    with warnings.catch_warnings():
        warnings.simplefilter("ignore")
        sa_models_by_table_names = getattr(Cache, 'models', {})

    for model in models:

        table_name = model._meta.db_table
        mixin = getattr(model, 'aldjemy_mixin', None)
        bases = (mixin, BaseSQLAModel) if mixin else (BaseSQLAModel, )
        table = tables[table_name]

        # because querying happens on sqlalchemy side, we can use only one
        # type of queries for alias, so we use 'read' type
        sa_model = type(model._meta.object_name, bases,
                        {'table': table,

def get_meta():
    if not getattr(Cache, 'meta', None):
        Cache.meta = MetaData()
    return Cache.meta