A printed docket or other written notice, setting forth the style of the cause and the day that the same is set for trial or hearing, may be mailed, by registered mail, by the court clerk or opposing counsel, addressed to the Attorney General or the assistant Attorney General appearing as attorney of record for the State of Oklahoma, not less than ten (10) days prior to the date set for such trial or hearing, and the registry return of such notice shall be sufficient proof of the notice herein required. The court clerk is authorized to tax up as cost for each notice given twenty-five cents ($0.25).