(?) Python Pathname Change Question

# This checks for an existing path+file exists.
# so the full file path intending to be written
# /Volumes/Drive/Directory/File.ext
#
#If 'File.ext' already exists at /Volume/Drive/Directory
# The next would be:
# /Volumes/Drive/Directory/File01.ext
# /Volumes/Drive/Directory/File02.ext
# /Volumes/Drive/Directory/File03.ext
#
# I want to increment the directory path instead of
# the filename instead:
# /Volumes/Drive/Directory01/File.ext
# ...if that exists then next:
# /Volumes/Drive/Directory02/File.ext
#
# Any takers? :)
# Thanks!


  def _rename(self, old_filename, metadata):
        new_filename, ext = os.path.splitext(
            self.make_filename(old_filename, metadata))

        if old_filename == new_filename + ext:
            return old_filename

        new_dirname = os.path.dirname(new_filename)
        if not os.path.isdir(new_dirname):
            os.makedirs(new_dirname)
        tmp_filename = new_filename
        i = 1
        while (not pathcmp(old_filename, new_filename + ext)
               and os.path.exists(new_filename + ext)):
            new_filename = "%s (%d)" % (tmp_filename, i)
            i += 1
        new_filename = new_filename + ext
        log.debug("Moving file %r => %r", old_filename, new_filename)
        shutil.move(old_filename, new_filename)
        return new_filename