Unlock Item

Hello I written Method to unlock itemtype but I want to lock items under itemtype when I logout from aras innovator. Innovator inn = this.getInnovator(); String AML="<AML><Item type='Design_request' action='unlock' id='43B44552B03543779386795B2F66D525'></Item></AML>"; Item result = inn.applyAML(AML); return this;