title: Tried to get values by list keys
body: <p>Tried to get values by list keys</p>
  
  <p>wrote Zabbix API request</p>
  
  <pre><code>zabbix_get= \
      {
          "jsonrpc": "2.0",
          "method": "item.get",
          "params": {
              "output": "extend",
              "host": "server01",
              # "host": "server01"
              "search": {
                  "key_": 'vfs.fs.size[/data,free]','system.cpu.util.usage'
              },
              "sortfield": "name"
          },
          "auth": authToken.get("result"),
          "id": authToken.get("id")
      }
  </code></pre>
  
  <p>BUT returned null.</p>
  
  <p>How to solve this problem?</p>