code: def _GetNormalizedTimestamp(self):
      
      if self._normalized_timestamp is None:
        if (self._timestamp is not None and self._timestamp >= 0 and
            self._timestamp <= self._UINT64_MAX):
          self._normalized_timestamp = (
              decimal.Decimal(self._timestamp) / self._100NS_PER_SECOND)
          self._normalized_timestamp -= self._FILETIME_TO_POSIX_BASE
  
      return self._normalized_timestamp
docs: Retrieves the normalized timestamp.
  
      Returns:
        decimal.Decimal: normalized timestamp, which contains the number of
            seconds since January 1, 1970 00:00:00 and a fraction of second used
            for increased precision, or None if the normalized timestamp cannot be
            determined.