'Get a list of paths to all the cache files. These are all the files
in the root cache dir that end on the cache_suffix.'

def _list_cache_files(self):

    if (not os.path.exists(self._dir)):
        return []
    filelist = [os.path.join(self._dir, fname) for fname in glob.glob1(self._dir, ('*%s' % self.cache_suffix))]
    return filelist
