def rename_file_group_to_serial_nums(file_lst):
file_lst.sort()<EOL>c = <NUM_LIT:1><EOL>for f in file_lst:<EOL><INDENT>dirname = get_abspath(f.dirname())<EOL>fdest = f.joinpath(dirname, "<STR_LIT>".format(c) +<EOL>OUTPUT_DICOM_EXTENSION)<EOL>log.info('<STR_LIT>'.format(f, fdest))<EOL>f.rename(fdest)<EOL>c += <NUM_LIT:1><EOL><DEDENT>
Will rename all files in file_lst to a padded serial
    number plus its extension

    :param file_lst: list of path.py paths