def Request(self,force=0):
        """ Request roster from server if it were not yet requested 
            (or if the 'force' argument is set). """
        if self.set is None: self.set=0
        elif not force: return
        self._owner.send(Iq('get',NS_ROSTER))
        self.DEBUG('Roster requested from server','start')
 Request roster from server if it were not yet requested 
            (or if the 'force' argument is set). 
chrome-cordova/gcmServer/xmpp/roster.py