Question about updating event severity using GQL updateEvent mutation

Hi,
 

I have a question about the GQL updateEvent mutation.
 

I'm trying to use it to change the severity of an existing event, but I'm getting a Bad Request response when executing the mutation:

mutation changeEvent($eventId: ID!, $severity: String) {

  updateEvent(id: $eventId, severity: $severity) {

    id

  }

}

 

Is changing the event severity supported with this mutation? If it is, could you let me know how the severity value should be provided?

Thanks!