Unlimited repetitions are not subject to this restriction.

Grouping:

	(re)           numbered capturing group (submatch)
	(?P<name>re)   named & numbered capturing group (submatch)
	(?<name>re)    named & numbered capturing group (submatch)
	(?:re)         non-capturing group
	(?flags)       set flags within current group; non-capturing
	(?flags:re)    set flags during re; non-capturing