No, the constant is to be used as the format string?
You are not grasping how this is meant to work?
All it is, is a format string in the format required, but rather than having to remember the syntax each time, you just need to remember a name, and if you cannot do that, then all you need to do is review a certain module, where it is stored?
When you post code, post ALL the relevant code, not just a snippet which makes the code look incorrect.