code: def pick(dirname, pattern):
    '''
    Get the topology jars
    :param dirname:
    :param pattern:
    :return:
    '''
    file_list = fnmatch.filter(os.listdir(dirname), pattern)
    return file_list[0] if file_list else Nonf pick(dirname, pattern):
    '''
    Get the topology jars
    :param dirname:
    :param pattern:
    :return:
    '''
    file_list = fnmatch.filter(os.listdir(dirname), pattern)
    return file_list[0] if file_list else None
docs: Get the topology jars
    :param dirname:
    :param pattern:
    :return: