def _parse_start_time(self, start_time_string):
        """Parse the time window start time.

        Parse the start time from the expected timestamp format to Python
        datetime format. Must be in UTC time.

        Args:
            start_time_string: (str) Timestamp in format YYYY-MM-DDTHH-mm-SS.

        Returns:
            datetime: Python datetime for set timestamp string.
        """
        try:
            timestamp = (
                datetime.datetime.strptime(start_time_string,
                                           '%Y-%m-%dT%H:%M:%SZ'))
            return utils.make_datetime_utc_aware(timestamp)
        except __HOLE__:
            raise SelectorParseError('UnsupportedSubsetDateFormat')
dataset/ETHPy150Open m-lab/telescope/telescope/selector.py/SelectorFileParser._parse_start_time