Haven't used yet, but this should be named the Python tool of the year. `pip freeze` is broken, this is the solution. I didn't even know it was possible to do

Haven't used yet, but this should be named the Python tool of the year. `pip freeze` is broken, this is the solution. I didn't even know it was possible to do this sort of thing with Python packages. -- Also, you should add the description to the Show HN submission: "Like `pip freeze` but lists only the packages that are not dependencies of installed packages."