code: def hdr_vals_for_overscan(root):
      
      with fits.open(root + '_spt.fits') as hdu:
          spthdr = hdu[0].header
      with fits.open(root + '_raw.fits') as hdu:
          prihdr = hdu[0].header
      xstart = spthdr['SS_A1CRN']
      ystart = spthdr['SS_A2CRN']
      xsize = spthdr['SS_A1SZE']
      ysize = spthdr['SS_A2SZE']
      ccdamp = prihdr['CCDAMP']
  
      return ccdamp, xstart, ystart, xsize, ysize
docs: Retrieve header keyword values from RAW and SPT
      FITS files to pass on to :func:`check_oscntab` and
      :func:`check_overscan`.
  
      Parameters
      ----------
      root : str
          Rootname of the observation. Can be relative path
          to the file excluding the type of FITS file and
          extension, e.g., '/my/path/jxxxxxxxq'.
  
      Returns
      -------
      ccdamp : str
          Amplifiers used to read out the CCDs.
  
      xstart : int
          Starting column of the readout in detector
          coordinates.
  
      ystart : int
          Starting row of the readout in detector
          coordinates.
  
      xsize : int
          Number of columns in the readout.
  
      ysize : int
          Number of rows in the readout.