Logbook log service prepends text, how to avoid that?

Hi, I am planing with python_scripts and writing stuff to logbook. This works so far. But when I do this. HASS alyways adds “ausgelöst durch Dienst Logbuch: Protokollieren” (from German translated “Triggered by service Logbook: Logging”).

How can I avoid that?

Example:
hass.services.call('logbook','log',{'name':'covers.test','message':'testmessage','entity_id':'covers.test'}