Super useful for when you don't know what are you missing and get a type signature for it.
It's mostly useful for when you declare some `const foo: (bar: Bar) => Whatever` and in the midst of your implementation you don't know what you're missing.
Requires an advanced level in TS to be used to the max.
https://gcanti.github.io/fp-ts/modules/function.ts.html#hole
https://effect-ts.github.io/effect/effect/Function.ts.html#h...