detecting and creating directories

[Fredrik Lundh]

Steve wrote:

> import os
> path = "/usr/tmp/newdir"
> if os.path.exists(path):
>     if not os.path.isdir(path):
>         raise ValueError, "%s exists but is not a directory" % path
> else:
>     os.mkdir(path)

for ten extra points, explain why this is a lousy way to
do this.

</F>