'Called by the ISAPI framework to get the extension version
The default implementation uses the classes docstring to
set the extension description, and uses the classes
filter_flags attribute to set the ISAPI filter flags - you
must specify filter_flags in your class.'

def GetFilterVersion(self, fv):

    if (self.filter_flags is None):
        raise RuntimeError('You    must    specify    the    filter    flags')
    if (fv is not None):
        fv.Flags = self.filter_flags
        fv.FilterDesc = self.__doc__
