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

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

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

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