code: def request_service(self, type, id=0):
          
          srvs = self.services_by_name.get(type)
          if not srvs:
              return
  
          ser = srvs[id]
  
          if not ser.system:
              ser.setup_system(self, id=id)
          return ser
docs: Used by Sensors/Actuators/other services that need to use other services for their
              operations.