    class UserManagerToFile(UserManager):

        ## Init ##
        def __init__(self, userClass=None):
        def initNextSerialNum(self):

        ## WebKit integration ##
        def wasInstalled(self, owner):

        ## File storage specifics ##
        def userDir(self):
        def setUserDir(self, userDir):
        def loadUser(self, serialNum, default=NoDefault):
        def scanSerialNums(self):

        ## UserManager customizations ##
        def setUserClass(self, userClass):

        ## UserManager concrete methods ##
        def nextSerialNum(self):
        def addUser(self, user):
        def userForSerialNum(self, serialNum, default=NoDefault):
        def userForExternalId(self, externalId, default=NoDefault):
        def userForName(self, name, default=NoDefault):
        def users(self):
        def activeUsers(self):
        def inactiveUsers(self):

        ## Encoder/decoder ##
        def encoder(self):
        def decoder(self):
        def setEncoderDecoder(self, encoder, decoder):

    class UserMixIn:
        def filename(self):
        def save(self):
        def __init__(self, mgr, filterFunc=None):
        def __getitem__(self, index):
        def __len__(self):