def create_psfmodel(im, cyx, **parameters):
    """Create a PSF model, ignoring the actual target

        Examples
        --------
        >>> from astropy.io import fits
        >>> from sbpy.imageanalysis import centroid, PSFSubtraction # doctest: +SKIP
        >>> import matplotlib.pyplot as plt # doctest: +SKIP
        >>> hdu = fits.open('test.fits') # doctest: +SKIP
        >>> cyx = centroid(hdu[0].data, (21, 45)) # doctest: +SKIP
        >>> psfmodel = PSFSubtraction(hdu[0].data, cyx) # doctest: +SKIP
        >>> plt.imshow(psfmodel) # doctest: +SKIP

        not yet implemented

        """
