Using private Nix flake inputs

I want to use Nix flakes for some projects at work. Those projects live in private Gitlab repositories that I use SSH keys to access. Furthermore, the project layout doesn’t mirror the usual GitHub namespace/project convention, but is something more like Company/Prefix/Username/Something/project . Nix’s flake input mechanisms do not like this, and figuring out how to get them to cooperate was a…