Sum together all values SNMP tree, Zabbix

[{
 "{#SNMPVALUE}": "1"
}, {
 "{#SNMPVALUE}": "1"
}, {
 "{#SNMPVALUE}": "2"
}, {
 "{#SNMPVALUE}": "2"
}, {
 "{#SNMPVALUE}": "2"
}, {
 "{#SNMPVALUE}": "2"
}, {
 "{#SNMPVALUE}": "1"
}]

JSON preprocessing step:

$[*]["{#SNMPVALUE}"].sum()