[onkyo] sendCommand(REFRESH) does not work

I want to use the REFRESH command of the onkyo binding to get the current volume value.

This is working via console.

openhab> smarthome:send avr1Z1_Volume REFRESH
Command has been sent successfully.
2017-07-08 20:42:57.526 [ItemCommandEvent          ] - Item 'avr1Z1_Volume' received command REFRESH

But it does not work when I include the command in a rule or script.

sendCommand(avr1Z1_Volume, REFRESH)
2017-07-08 20:40:54.855 [ERROR] [.script.engine.ScriptExecutionThread] - Rule 'Test UNDEF2': An error occurred during the script execution: The name 'REFRESH' cannot be resolved to an item or type.

I found the solution.

You have to put the command in quotes.

sendCommand(avr1Z1_Volume, "REFRESH")