Helper function used in service implementations to finish handling invocations of the <link linkend="gdbus-method-org-freedesktop-ModemManager1-Modem.
Command">Command</link> D-Bus method. If you instead want to finish handling an invocation by returning an error,
use return_error or similar.
This method will free invocation, you cannot use it afterwards.
| this |
A GdbusModem. |
| invocation | |
| response |
Parameter to return. |