The error message : Not a single item

Hello, This script has the error message when I vote in the workflow: Not a single item I just want the script can determine if the [classification] column not filled by user, and it can show message "Please key classification!" Could anyone help me please? Thank you very much. Innovator inn = this.getInnovator(); Item itemQ = inn.newItem("MI_ISSUE_TODOLIST","get"); itemQ.setAttribute("select","classification"); itemQ.setProperty("id",itemQ.getID()); itemQ = itemQ.apply(); string OwnID2=itemQ.getProperty("classification"); if (OwnID2 == "") { return inn.newError("Please key classification!"); } return this;