[PyQt] subclassing QSqlTableModel

[paolo at paolodestefani.it]

I'm using python 3.2 and pyqt 4.8.5 on windows 7 32bit
I'm trying to understand how subclassing QSqlTableModel works and i don't
understand why this code fail:

class StaffModel(QSqlTableModel):
    def __init__(self, parent):
        QSqlTableModel.__init__(self, parent)
        self.setTable("staff")

    def flags(self, index):
        QSqlTableModel.flags(self, index)

I use this model in a tableview and what i get is this messages:

TypeError: invalid result type from StaffModel.flags()
TypeError: invalid result type from StaffModel.flags()
TypeError: invalid result type from StaffModel.flags()
TypeError: invalid result type from StaffModel.flags()
(...)

If i delete the flags() method, so that StaffModel is the same of
QSqlTableModel but with 'preloaded' the table name, everything works as
expected.
Looks Like i can not redefine methods ?

Thanks.

Paolo