xxxxx.xxxxx.adgroup.delete
        ===================================
        删除一个推广组

def delete(self, group_id, nick=None):
        '''xxxxx.xxxxx.adgroup.delete
        ===================================
        删除一个推广组'''
        request = TOPRequest('xxxxx.xxxxx.adgroup.delete')
        request['group_id'] = group_id
        if nick!=None: request['nick'] = nick
        self.create(self.execute(request), fields=['success','result','success','result_code','result_message'], models={'result':ADGroup})
        return self.result