hello, I'v a discovery custom template that discover how many users use proftpd: proftpd.users[flow, {$USRNM}].I would like to add all the flows to have a graph with the sum of the flows displayed, so I used the function: grpsum["proftpd","proftpd.user[flows,],last,0] but zabbix say: expected numeric token at "grpsum..."