throws ParseException
{
String[] edz = getEraDatetimeZone(datetimeIn);
String datetime = edz[1];
if (datetime == null)
return new XNumber(Double.NaN);
String[] formats = {dt, d, gym, gy};
double dbl = getNumber(datetime, formats, Calendar.YEAR);
if (dbl == Double.NaN)
return new XNumber(Double.NaN);
int yr = (int)dbl;
return new XBoolean(yr % 400 == 0 || (yr % 100 != 0 && yr % 4 == 0));
}