def get_file_name(file_name):
    """
    converts name of file with directory path
    to file name alone
    /dir/dir2/file_name.ext => file_name.ext
    :param file_name:
    :return:
    """
    by_dir = file_name.split('/')
    file_name = by_dir[len(by_dir) - 1]
    return file_name
