@Nullable
public Calendar detectDate(String input) {
checkNotNull(input);
Time.setTimeZone(getTimeZone());
Options opt = new com.sk89q.jchronic.Options();
opt.setNow(Calendar.getInstance(getTimeZone()));
Span date = Chronic.parse(input, opt);
if (date == null) {
return null;
} else {
return date.getBeginCalendar();