code: def add_service(self, service_type, service_endpoint=None, values=None):
          
          if isinstance(service_type, Service):
              service = service_type
          else:
              service = Service(service_endpoint, service_type, values, did=self._did)
          logger.debug(f'Adding service with service type {service_type} with did {self._did}')
          self._services.append(service)
docs: Add a service to the list of services on the DDO.
  
          :param service_type: Service
          :param service_endpoint: Service endpoint, str
          :param values: Python dict with serviceDefinitionId, templateId, serviceAgreementContract,
          list of conditions and consume endpoint.