<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _ConvertToTimestamp(self, date, time, timezone):
 """Converts date and time values into a timestamp. The date and time are made up of two strings, the date and the time, separated by a tab. The time is in local time. The month and day can be either 1 or 2 characters long, e.g.: 7/30/2013\\t10:22:48 AM Args: date (str):
 date. time (str):
 time. timezone (pytz.timezone):
 timezone of the date and time. Returns: int: a timestamp integer containing the number of micro seconds since January 1, 1970, 00:00:00 UTC. Raises: TimestampError: if the timestamp is badly formed or unable to transfer the supplied date and time into a timestamp. """

    # TODO: check if this is correct, likely not date or not time
    # is more accurate.
    if not date and not time:
      raise errors.TimestampError(
          'Unable to extract timestamp from McAfee AV logline.')

    # TODO: Figure out how McAfee sets Day First and use that here.
    # The in-file time format is '07/30/2013\t10:22:48 AM'.
    try:
      time_string = '{0:s} {1:s}'.format(date, time)
    except UnicodeDecodeError:
      raise errors.TimestampError('Unable to form a timestamp string.')

    return timelib.Timestamp.FromTimeString(time_string, timezone=timezone)