taobao.fenxiao.discount.update 修改等级折扣
        
        修改等级折扣

def update(self, session, **kwargs):
        '''taobao.fenxiao.discount.update 修改等级折扣
        
        修改等级折扣'''
        request = TOPRequest('taobao.fenxiao.discount.update')
        for k, v in kwargs.iteritems():
            if k not in ('discount_id', 'discount_name', 'discount_status', 'detail_ids', 'target_types', 'target_ids', 'discount_types', 'discount_values', 'detail_statuss') and v==None: continue
            request[k] = v
        self.create(self.execute(request, session), fields=['is_success',])
        return self.is_success