**Tell us what’s happening:**

the last challenge [The `sum`

function uses the `...`

spread operator on the `args`

parameter.]

help me to complete this condition has not completed yet.

**Your code so far**

```
const sum = (function() {
"use strict";
return function sum(...x) {
const args = [...x];
return args.reduce((a, b) => a + b, 0);
};
})();
console.log(sum(1, 2, 3)); // 6
```

**Your browser information:**

User Agent is: `Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36`

.