def validateInterval(self, startTime, endTime):
start = int(startTime)<EOL>end = int(endTime)<EOL>if start > end:<EOL><INDENT>raise Exception("<STR_LIT>")<EOL><DEDENT>
Helper function to validate interval.
An interval is valid if starttime and endtime are integrals,
and starttime is less than the endtime.
Raises exception if interval is not valid.