def sql_dequote_string(s: str) -> str:
    """
    Reverses :func:`sql_quote_string`.
    """
    if len(s) < 2 or s[0] != SQUOTE or s[-1] != SQUOTE:
        raise ValueError("Not an SQL string literal")
    s = s[1:-1]  # strip off the surrounding quotes
    return s.replace(DOUBLE_SQUOTE, SQUOTE)