> To understand the entirety of that first signature you need to grasp is: ... ...4. The unit type (), which is basically a 0-tuple, i.e. a type that carries n

> To understand the entirety of that first signature you need to grasp is: ... ...4. The unit type (), which is basically a 0-tuple, i.e. a type that carries no information, and generally replaces the use of `void` in C-like languages. (Rust also has a proper void type, i.e. a type for something that cannot occur, but that's denoted by ! and is quite different from the unit type.) It's not a hard concept, but it may be a bit unfamiliar if you havent worked with functionalish languages before.