the first test on this one is fairly easy, but there are a few things to think about(or google) here for the later tests:
- how to remove a single element from an array
- how to deal with multiple optional arguments in a javascript function
- [Check this link](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/arguments). Scroll down to the bit about `Array.from` or the spread operator.