def backslashcase(string):
str1 = re.sub(r"<STR_LIT:_>", r"<STR_LIT:\\>", snakecase(string))<EOL>return str1<EOL>
Convert string into spinal case.
    Join punctuation with backslash.

    Args:
        string: String to convert.

    Returns:
        string: Spinal cased string.