Don't use `Function` as a type

Question

function (fn:Function, time: number) {
    let date = 0;
    return function (): void {
            fn();
    };
};

这样写的话会报错Don't use Function as a type，其他类型的话fn()会报错，那么如何来对fn进行约束呢，dl们怎么写呢