get list of component IDs with parameters for a given system ID

def get_component_id_list(self, system_id):
        '''get list of component IDs with parameters for a given system ID'''
        ret = []
        for (s,c) in self.mpstate.mav_param_by_sysid.keys():
            if s == system_id:
                ret.append(c)
        return ret