code: def get_beam(self, ra, dec):
          
          if self.data is None:
              return self.wcshelper.beam
          else:
              psf = self.get_psf_sky(ra, dec)
              if not all(np.isfinite(psf)):
                  return None
              return Beam(psf[0], psf[1], psf[2])
docs: Get the psf as a :class:`AegeanTools.fits_image.Beam` object.
  
          Parameters
          ----------
          ra, dec : float
              The sky position (degrees).
  
          Returns
          -------
          beam : :class:`AegeanTools.fits_image.Beam`
              The psf at the given location.