func parseTimeZone(value string) (length int, ok bool) {
	if len(value) < 3 {
		return 0, false
	}
	// Special case 1: ChST and MeST are the only zones with a lower-case letter.
	if len(value) >= 4 && (value[:4] == "ChST" || value[:4] == "MeST") {
		return 4, true
	}
	// Special case 2: GMT may have an hour offset; treat it specially.
	if value[:3] == "GMT" {
		length = parseGMT(value)

	{"GMT+00 hi there", 6, true},
	{"GMT+", 3, true},
	{"GMT+3", 5, true},
	{"GMT+a", 3, true},
	{"GMT+3a", 5, true},
	{"GMT-5 hi there", 5, true},
	{"GMT-51 hi there", 3, true},
	{"ChST hi there", 4, true},
	{"MeST hi there", 4, true},
	{"MSDx", 3, true},
	{"MSDY", 0, false}, // four letters must end in T.
	{"ESAST hi", 5, true},
	{"ESASTT hi", 0, false}, // run of upper-case letters too long.