def get_argument_endtime(self):
try:<EOL><INDENT>endtime = self.get_argument(constants.PARAM_ENDTIME)<EOL>return endtime<EOL><DEDENT>except tornado.web.MissingArgumentError as e:<EOL><INDENT>raise Exception(e.log_message)<EOL><DEDENT>
Helper function to get endtime argument.
Raises exception if argument is missing.
Returns the endtime argument.