How to Show a List As Radio Button?

{
      title: "Num Cols",
      name: "cols",
      type: "array",
      of: [{ type: "string" }],
      options: {
        list: [
          { title: "One Column", value: "1" },
          { title: "Two Columns", value: "2" },
          { title: "Three Col", value: "3" }
        ],
        layout: "radio",
        direction: "horizontal"
      }
    }

{
      title: "Num Cols",
      name: "cols",
      type: "string",
      options: {
        list: [
          { title: "One Column", value: "1" },
          { title: "Two Columns", value: "2" },
          { title: "Three Col", value: "3" }
        ],
        layout: "radio",
        direction: "horizontal"
      }
    }