Plenty of languages have this convention. For example, in Elixir it's customary to have something like `getUser` that returns either {:ok, the_user} or {:error

Plenty of languages have this convention. For example, in Elixir it's customary to have something like `getUser` that returns either {:ok, the_user} or {:error, reason} alongside `getUser!`, the `!` indicating that in case of error it will throw. Of course, a better approach is to not throw at all, and leverage a type system to force the consumer to deal with potential error: `getUser: Try[Option[User]]` for example. More verbose, and forces you to handle all the cases, but safer and less error prone.