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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _process_input_wcs_single(fname, wcskey, updatewcs):
 """ See docs for _process_input_wcs. This is separated to be spawned in parallel. """

    if wcskey in ['', ' ', 'INDEF', None]:
        if updatewcs:
            uw.updatewcs(fname, checkfiles=False)
    else:
        numext = fileutil.countExtn(fname)
        extlist = []
        for extn in range(1, numext + 1):
            extlist.append(('SCI', extn))
        if wcskey in string.ascii_uppercase:
            wkey = wcskey
            wname = ' '
        else:
            wname = wcskey
            wkey = ' '
        altwcs.restoreWCS(fname, extlist, wcskey=wkey, wcsname=wname)
    # make an asn table at the end
    # Make sure there is a WCSCORR table for each input image
    if wcskey not in ['', ' ', 'INDEF', None] or updatewcs:
        wcscorr.init_wcscorr(fname)