code: def write(self,fitsname=None,wcs=None,archive=True,overwrite=False,quiet=True):
          
          ## Start by making sure all derived values are in sync with CD matrix
          self.update()
  
          image = self.rootname
          _fitsname = fitsname
  
          if image.find('.fits') < 0 and _fitsname is not None:
              # A non-FITS image was provided, and openImage made a copy
              # Update attributes to point to new copy instead
              self.geisname = image
              image = self.rootname = _fitsname
  
          # Open image as writable FITS object
          fimg = fileutil.openImage(image, mode='update', fitsname=_fitsname)
  
          _root,_iextn = fileutil.parseFilename(image)
          _extn = fileutil.getExtn(fimg,_iextn)
  
          # Write out values to header...
          if wcs:
              _wcsobj = wcs
          else:
              _wcsobj = self
  
          for key in _wcsobj.wcstrans.keys():
              _dkey = _wcsobj.wcstrans[key]
              if _dkey != 'pscale':
                  _extn.header[key] = _wcsobj.__dict__[_dkey]
  
          # Close the file
          fimg.close()
          del fimg
          if archive:
              self.write_archive(fitsname=fitsname,overwrite=overwrite,quiet=quiet)
docs: Write out the values of the WCS keywords to the
          specified image.
  
          If it is a GEIS image and 'fitsname' has been provided,
          it will automatically make a multi-extension
          FITS copy of the GEIS and update that file. Otherwise, it
          throw an Exception if the user attempts to directly update
          a GEIS image header.
  
          If archive=True, also write out archived WCS keyword values to file.
          If overwrite=True, replace archived WCS values in file with new values.
  
          If a WCSObject is passed through the 'wcs' keyword, then the WCS keywords
          of this object are copied to the header of the image to be updated. A use case
          fo rthis is updating the WCS of a WFPC2 data quality (_c1h.fits) file
          in order to be in sync with the science (_c0h.fits) file.