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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 make_xml_name(self, source_name, galkey, fullpath):
 """ 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 """

        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)