code: def get_raise_brok(self, host_name, service_name=''):
          
          data = self.serialize()
          data['host'] = host_name
          if service_name != '':
              data['service'] = service_name
  
          return Brok({'type': 'downtime_raise', 'data': data})
docs: Get a start downtime brok
  
          :param host_name: host concerned by the downtime
          :type host_name
          :param service_name: service concerned by the downtime
          :type service_name
          :return: brok with wanted data
          :rtype: alignak.brok.Brok