code: def get_valid_filename(s):
      
      s = get_valid_filename_django(s)
      filename, ext = os.path.splitext(s)
      filename = slugify(filename)
      ext = slugify(ext)
      if ext:
          return "%s.%s" % (filename, ext)
      else:
          return "%s" % (filename,)
docs: like the regular get_valid_filename, but also slugifies away
      umlauts and stuff.