[Zope] User Folder

[javi lopez]

hello and thanks for your help..
I did a plugin for PAS and iwant to read the users from de acl_users
to validate and i did this:

def authenticateCredentials(self, credentials):
        """ Authentication Part """

        acl = self.getUserFolder() // Is this ok?
        login = credentials.get('login', '')
        password = credentials.get('password', '')

        if not acl or not login or not password:
            return (None, None)

        user = acl.getUser(login)
        if user is None:
            return (None, None)
        elif user and (user.getPassword() == password):
            return ( user.getId(), login )

        return (None, None)

But it don´t work. Can you help me??? how can i do it??