code: def get_grouped_psf_model(template_psf_model, star_group, pars_to_set):
      
  
      group_psf = None
  
      for star in star_group:
          psf_to_add = template_psf_model.copy()
          for param_tab_name, param_name in pars_to_set.items():
              setattr(psf_to_add, param_name, star[param_tab_name])
  
          if group_psf is None:
              # this is the first one only
              group_psf = psf_to_add
          else:
              group_psf += psf_to_add
  
      return group_psf
docs: Construct a joint PSF model which consists of a sum of PSF's templated on
      a specific model, but whose parameters are given by a table of objects.
  
      Parameters
      ----------
      template_psf_model : `astropy.modeling.Fittable2DModel` instance
          The model to use for *individual* objects.  Must have parameters named
          ``x_0``, ``y_0``, and ``flux``.
      star_group : `~astropy.table.Table`
          Table of stars for which the compound PSF will be constructed.  It
          must have columns named ``x_0``, ``y_0``, and ``flux_0``.
  
      Returns
      -------
      group_psf
          An `astropy.modeling` ``CompoundModel`` instance which is a sum of the
          given PSF models.