xxxxx.xxxxx.adgroup.catmatch.update
        ===================================
        更新一个推广组的类目出价，可以设置类目出价、是否使用默认出价、是否打开类目出价

def update(self, adgroup_id, catmatch_id, max_price, is_default_price, online_status, nick=None):
        '''xxxxx.xxxxx.adgroup.catmatch.update
        ===================================
        更新一个推广组的类目出价，可以设置类目出价、是否使用默认出价、是否打开类目出价'''
        request = TOPRequest('xxxxx.xxxxx.adgroup.catmatch.update')
        request['adgroup_id'] = adgroup_id
        request['catmatch_id'] = catmatch_id
        request['max_price'] = max_price
        request['is_default_price'] = is_default_price
        request['online_status'] = online_status
        if nick!=None: request['nick'] = nick
        self.create(self.execute(request), fields=['success','result','success','result_code','result_message'], models={'result':ADGroupCatmatch})
        return self.result