code: def free_sources_by_name(self, names, free=True, pars=None,
                               **kwargs):
          
  
          if names is None:
              return
  
          names = [names] if not isinstance(names, list) else names
          names = [self.roi.get_source_by_name(t).name for t in names]
          srcs = [s for s in self.roi.sources if s.name in names]
          for s in srcs:
              self.free_source(s.name, free=free, pars=pars, **kwargs)
  
          return srcs
docs: Free all sources with names matching ``names``.
  
          Parameters
          ----------
          names : list
              List of source names.
  
          free : bool
              Choose whether to free (free=True) or fix (free=False)
              source parameters.
  
          pars : list
              Set a list of parameters to be freed/fixed for each
              source.  If none then all source parameters will be
              freed/fixed.  If pars='norm' then only normalization
              parameters will be freed.
  
          Returns
          -------
          srcs : list
              A list of `~fermipy.roi_model.Model` objects.