How to use the relstorage.storage.RelStorage function in RelStorage

adapter = PostgreSQLAdapter(dsn=dsn, options=options)
    rs = RelStorage(adapter=adapter, options=options)
    db = DB(rs)
    try:
        conn = db.open()
        rootobj = conn.root()
        if not IDatabase.providedBy(rootobj):
            alsoProvides(rootobj, IDatabase)
        transaction.commit()
    except:  # noqa
        pass
    finally:
        rootobj = None
        conn.close()
        db.close()
    rs = RelStorage(adapter=adapter, options=options)
    db = RequestAwareDB(rs, **config)
    return Database(key, db)

def RelStorageConfigurationFactory(key, dbconfig):
    if not RELSTORAGE:
        raise Exception("You must install the relstorage package before you can use "
                        "it as a dabase adapter.")
    config = dbconfig.get('configuration', {})
    options = Options(**dbconfig['options'])
    if dbconfig['type'] == 'postgres':
        from relstorage.adapters.postgresql import PostgreSQLAdapter
        dsn = "dbname={dbname} user={user} host={host} password={password} port={port}".format(**dbconfig['dsn'])  # noqa
        adapter = PostgreSQLAdapter(dsn=dsn, options=options)
    rs = RelStorage(adapter=adapter, options=options)
    db = DB(rs)
    try:
        conn = db.open()
        rootobj = conn.root()
        if not IDatabase.providedBy(rootobj):
            alsoProvides(rootobj, IDatabase)
        transaction.commit()
    except:  # noqa
        pass
    finally:
        rootobj = None
        conn.close()
        db.close()
    rs = RelStorage(adapter=adapter, options=options)
    db = RequestAwareDB(rs, **config)
    return Database(key, db)

def factory():
                adapter = adapter_factory(options)
                storage = RelStorage(adapter=adapter, options=options)
                if demostorage:
                    storage = DemoStorage(base=storage)
                return storage
            return factory, unused