Sqlalchemyは、添付された複数のSQLiteデータベースファイルでうまく機能しますか？

from sqlalchemy import create_engine, MetaData, Table,Column,Integer,select
from sqlalchemy.orm import mapper, sessionmaker
from sqlite3 import dbapi2 as sqlite
from sqlalchemy.engine.reflection import Inspector

class Bookmarks(object):
    pass

class BookmarksB(object):
    pass



def loadSession():
    engine = create_engine('sqlite://', echo=True)
    engine.execute("attach database 'database_b' as BB;")
    engine.execute("attach database 'database_a' as AA;")
    metadata = MetaData(engine)


    inspector = Inspector.from_engine(engine)
    print inspector.get_table_names()

    moz_bookmarks = Table('table_a', metadata,Column("id", Integer, primary_key=True),schema='AA', autoload=True)
    mapper(Bookmarks, moz_bookmarks)
    moz_bookmarksB = Table('table_b', metadata,Column("id", Integer, primary_key=True),schema='BB', autoload=True)
    mapper(BookmarksB, moz_bookmarksB)

    Session = sessionmaker(bind=engine)
    session = Session()
    return session

if __name__ == "__main__":
    session = loadSession()
    res = session.query(Bookmarks).all()
    for m in res:
        print m.msisdn,m.id

    #print list(select([moz_bookmarks, moz_bookmarksB], moz_bookmarks.c.b_id == moz_bookmarksB.c.id).execute())