Pyramid将models.py文件的内容分布到多个文件的方法

myapp
    __init__.py
    scripts
        __init__.py
        initialize_db.py
    models
        __init__.py
        meta.py
        foo.py
        moo.py

Base = declarative_base()
DBSession = scoped_session(sessionmaker(extension=ZopeTransactionExtension))

from .meta import DBSession
from .foo import Foo
from .moo import Moo