public class TriggerHandlerOnKnowledge {
    public static void run() {
        if(Trigger.isAfter && Trigger.isInsert) {
            publishHighPriority((List<Knowledge__kav>)Trigger.new);            
        }
    }

    private static void publishHighPriority(List<Knowledge__kav> articles) {
        for(Knowledge__kav article: articles) {
            if(article.priority__c == 'High') {
                KbManagement.PublishingService.publishArticle(article.KnowledgeArticleId, false);
            }
        }
    }
}