def timestamp_from_string(self, timestamp):
        formats = (self.TIMESTAMP_FORMAT,
                   self.DEFAULT_TIMESTAMP_FORMAT,
                   self.OLD_DEFAULT_TIMESTAMP_FORMAT)
        for format_string in formats:
            try:
                history_time = time.strptime(timestamp, format_string)
            except ValueError:
                pass
            else:
                return int(time.mktime(history_time))
        self.debug('The timestamp "%s" does not match any of the formats %s' % (timestamp, formats))
try with the user-defined timestamp then try the default timestamp.
dataset/ETHPy150Open FichteFoll/FileHistory/file_history.py/FileHistory.timestamp_from_string