It’s a bit confusing, but in this case, the arguments are “optional” more like in a C# sense, meaning that you don’t need to supply the parameter at all.
For example, here I only supply the url and the method:
let response = Http.Request(url = "www.somewebsite.com", httpMethod = "GET")
If you want to explicitly pass None you can prefix the parameter with a question mark:
let response = Http.Request(url = "www.somewebsite.com", httpMethod = "GET", ?query = None)
If you want to know more about Optional parameters, here are the docs 