def stsci(hdulist):
    """For STScI GEIS files, need to do extra steps."""
    instrument = hdulist[0].header.get('INSTRUME', '')
    if instrument in ('WFPC2', 'FOC'):
        rootname = hdulist[0].header.get('ROOTNAME', '')
        filetype = hdulist[0].header.get('FILETYPE', '')
        for i in range(1, len(hdulist)):
            hdulist[i].name = filetype
            hdulist[i]._extver = i
            hdulist[i].header['EXPNAME'
                ] = rootname, '9 character exposure identifier'
            hdulist[i].header['EXTVER'] = i, 'extension version number'
            hdulist[i].header['EXTNAME'] = filetype, 'extension name'
            hdulist[i].header['INHERIT'] = True, 'inherit the primary header'
            hdulist[i].header['ROOTNAME'
                ] = rootname, 'rootname of the observation set'
