def METHOD_NAME(
    s: Union[str, Iterable[str]], re_escape: bool = True
) -> str:
    def is_consecutive(c):
        c_int = ord(c)
        is_consecutive.prev, prev = c_int, is_consecutive.prev
        if c_int - prev > 1:
            is_consecutive.value = next(is_consecutive.counter)
        return is_consecutive.value
    is_consecutive.prev = 0
    is_consecutive.counter = itertools.count()
    is_consecutive.value = -1
    def escape_re_range_char(c):
        return "\\" + c if c in r"\^-][" else c
    def no_escape_re_range_char(c):
        return c
    if not re_escape:
        escape_re_range_char = no_escape_re_range_char
    ret = []
    s = "".join(sorted(set(s)))
    if len(s) > 3:
        for _, chars in itertools.groupby(s, key=is_consecutive):
            first = last = next(chars)
            last = collections.deque(
                itertools.chain(iter([last]), chars), maxlen=1
            ).pop()
            if first == last:
                ret.append(escape_re_range_char(first))
            else:
                sep = "" if ord(last) == ord(first) + 1 else "-"
                ret.append(
                    "{}{}{}".format(
                        escape_re_range_char(first), sep, escape_re_range_char(last)
                    )
                )
    else:
        ret = [escape_re_range_char(c) for c in s]
    return "".join(ret)