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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 get_pixbeam(self, ra, dec):
 """ Get the psf at the location specified in pixel coordinates. The psf is also in pixel coordinates. Parameters ra, dec : float The sky position (degrees). Returns ------- a, b, pa : float The psf semi-major axis (pixels), semi-minor axis (pixels), and rotation angle (degrees). If a psf is defined then it is the psf that is returned, otherwise the image restoring beam is returned. """

        # If there is no psf image then just use the fits header (plus lat scaling) from the wcshelper
        if self.data is None:
            return self.wcshelper.get_pixbeam(ra, dec)
        # get the beam from the psf image data
        psf = self.get_psf_pix(ra, dec)
        if not np.all(np.isfinite(psf)):
            log.warn("PSF requested, returned Null")
            return None
        return Beam(psf[0], psf[1], psf[2])