```"Given a function with parameter types `P1`, `P2`, ..., `Pn`,
return a function with a single parameter of tuple type
`[P1, P2, ..., Pn]`.

That is, if `fun` has type `W(X,Y,Z)` then `unflatten(fun)`
has type `W([X,Y,Z])`.

In the case of a variadic function, the returned function
has a single parameter whose type is a sequence type or
unterminated tuple type:

- if the given function has a single variadic parameter of
type `S*`, the returned function accepts `[S*]`,
- if the given function has a single variadic parameter of
type `S+`, the returned function accepts `[S+]`,
- if the given function has multiple parameters with types
`P1`, `P2`, ..., `Pn`, `S*`, the returned function
accepts `[P1, P2, ..., Pn, S*]`, or
- if the given function has multiple parameters with types
`P1`, `P2`, ..., `Pn`, `S+`, the returned function
accepts `[P1, P2, ..., Pn, S+]`."
see(`function flatten`)
tagged("Functions")
shared native Return unflatten<Return,Args>
(Return(*Args) flatFunction)(Args args)
given Args satisfies Anything[];
```