1、Flask模組中session與Flask-session元件中session的繼承關係：

　　Flask模組sessions.py：

class SessionInterface(object):
    def open_session(self, app, request):
        raise NotImplementedError()

    def save_session(self, app, session, response):
        raise NotImplementedError()

class SecureCookieSessionInterface(SessionInterface):
    
 
def open_session(self, app, request):
        pass

    def save_session(self, app, session, response):
        pass

　　flask-session元件sessions.py:

class SessionInterface(FlaskSessionInterface):
    pass

class NullSessionInterface(SessionInterface):
    pass
    
class RedisSessionInterface(SessionInterface):
    
 
pass
    
class MemcachedSessionInterface(SessionInterface):
    pass
    
class FileSystemSessionInterface(SessionInterface):
    pass
    
class MongoDBSessionInterface(SessionInterface):
    pass
    
class SqlAlchemySessionInterface(SessionInterface):
    pass