code: def list(self, service_rec=None, host_rec=None, hostfilter=None):
          
          return self.send.service_list(service_rec, host_rec, hostfilter)
docs: List a specific service or all services
  
          :param service_rec: t_services.id
          :param host_rec: t_hosts.id
          :param hostfilter: Valid hostfilter or None
          :return: [(svc.t_services.id, svc.t_services.f_hosts_id, svc.t_hosts.f_ipaddr,
               svc.t_hosts.f_hostname, svc.t_services.f_proto,
               svc.t_services.f_number, svc.t_services.f_status, svc.t_services.f_name,
               svc.t_services.f_banner), ...]