Not always default value can be expressed in Python. Current docstring for the match() method says "match(string[, pos[, endpos]])". For this particular case it can be written as "match(string, pos=0, endpos=sys.maxsize)". And this is very common case (see also str.find(sub[, start[, end]]), etc). Perhaps there are cases in which the default value is not PY_SSIZE_T_MAX and None is not accepted (as for dir_fd parameter in os functions).

So as minimum Argument Clinic can support sys.maxsize, and as maximum, it should support arbitrary values.