code: def __setRouterUpgradeThreshold(self, iThreshold):
          
          print 'call __setRouterUpgradeThreshold'
          try:
              cmd = 'routerupgradethreshold %s' % str(iThreshold)
              print cmd
              return self.__sendCommand(cmd) == 'Done'
          except Exception, e:
              ModuleHelper.WriteIntoDebugLogger("setRouterUpgradeThreshold() Error: " + str(e))
docs: set router upgrade threshold
  
          Args:
              iThreshold: the number of active routers on the Thread network
                          partition below which a REED may decide to become a Router.
  
          Returns:
              True: successful to set the ROUTER_UPGRADE_THRESHOLD
              False: fail to set ROUTER_UPGRADE_THRESHOLD