code: def make_xml_name(self, source_name, galkey, fullpath):
          
          format_dict = self.__dict__.copy()
          format_dict['sourcekey'] = self._name_factory.galprop_sourcekey(source_name=source_name,
                                                                          galpropkey=galkey)
          format_dict['fullpath'] = fullpath
          return self._name_factory.srcmdl_xml(**format_dict)
docs: Make the name of an xml file for a model definition for a set of merged rings
  
          Parameters
          ----------
  
          source_name : str
              The galprop component, used to define path to gasmap files
          galkey : str
              A short key identifying the galprop parameters
          fullpath : bool
              Return the full path name