How to use the select26.KQ_FILTER_WRITE function in select26

def _doWriteOrRead(self, selectable, fd, event):
        why = None
        inRead = False
        filter, flags, data, fflags = event.filter, event.flags, event.data, event.fflags
        if flags & KQ_EV_EOF and data and fflags:
            why = main.CONNECTION_LOST
        else:
            try:
                if filter == KQ_FILTER_READ:
                    inRead = True
                    why = selectable.doRead()
                if filter == KQ_FILTER_WRITE:
                    inRead = False
                    why = selectable.doWrite()
                if not selectable.fileno() == fd:
                    inRead = False
                    why = main.CONNECTION_LOST
            except:
                log.err()
                why = sys.exc_info()[1]

        if why:
            self._disconnectSelectable(selectable, why, inRead)

def removeWriter(self, writer):
        """
        Remove a Selectable for notification of data available to write.
        """
        fd = writer.fileno()
        if fd == -1:
            for fd, fdes in self._selectables.iteritems():
                if writer is fdes:
                    break
            else:
                return
        if fd in self._writes:
            self._writes.discard(fd)
            if fd not in self._reads:
                del self._selectables[fd]
            self._updateRegistration(fd, KQ_FILTER_WRITE, KQ_EV_DISABLE)