This is your intent until I finish implementing and then you complain that it doesn't also work with folders or large files and it doesn't work with any file system. Or you will complain if your colleague accesses your file without your permission.

Reality of software development is that the user would expect every single one of those things but they simply don't understand what they want up front.

There are three different aspects to consider in my experience; what the user says they want, what the user thinks they want and what the user actually wants.

The three can have substantial differences.