code: def _form_datetimes(days, msecs):
      
  
      all_datetimes = []
      for i in range(days.size):
          day = int(days[i])
          msec = msecs[i]
          scanline_datetimes = []
          for j in range(int(VALUES_PER_SCAN_LINE / 4)):
              usec = 1000 * (j * VIEW_TIME_ADJUSTMENT + msec)
              delta = (dt.timedelta(days=day, microseconds=usec))
              for k in range(4):
                  scanline_datetimes.append(delta.total_seconds())
          all_datetimes.append(scanline_datetimes)
  
      return np.array(all_datetimes, dtype=np.float64)
docs: Calculate seconds since EPOCH from days and milliseconds for each of IASI scan.