https://www.typescriptlang.org/play/?#code/FAMwrgdgxgLglgewgAgM5gLYYIYAoNwQBcEmARgKYBOANDgB4nnUCUTGlVyA3sMv8gA2FGGkzIAvMgAMAbj4CQCKrmGi4k5AQizkGgDxbs9ANQBGXXBMmWPBQP7oMyE1LjyHAqElQJhAOkEEAHNcJxYPAQBfYHtkKhEwKhQneRjgbwhfAKDQgCIAZUwcImQ8lzEsPAAmGgA2FgigA

https://flems.io/#0=N4IgZglgNgpgziAXAbVAOwIYFsZJAOgAsAXLKEAGhAGMB7NYmBvEAXwvW10QICsEqdBk2J4AOiACucGAAI4xAE4RqxCWLQbYxWRlkBeWQCYA3Box7DAZjNohcWrHxRaAcwAUGAJQnKIGbCqEPQIPEaIAAxsHCCYOHj41HACNPSMzDxsALqsQA

https://www.typescriptlang.org/play/?#code/JYOwLgpgTgZghgYwgAgIICFkG8BQzlxwBcyAzmFKAOYDceyARgySAK4C2D0dAvjjgBsIYAsgC82QkQBEACwgAraTzpCRDcZOLI5i6QBpGzaQBMApwEJldQcILMMNuBom58UnfKX76TEgCYcFX5nTTg6UIkGGiA

- En övningar till om interface.

- Övningar är konvertera till nytt format.