turning my function into a context manager

[Skaperen]

i have a function named "cd()". called with a directory name, it changes the process current working directory to that directory. called with no argument or None, it changes the process current working directory to the user home directory. i'm thinking of adding __enter__() and __exit__() so it can be a context manager on the with statement. on entry, it will save the current working directory before changing to the specified directory. on exit, it will restore the previous directory. i'm sure this has been done before, but i was re-reading PEP 343 again, tonight (a little slower this time).

i'm going through my other functions ("Skaperen's Function Collection") to see what else might be doable (and maybe useful, maybe not).