code: def get_instance_guid(self, service_name):
          
          summary = self.space.get_space_summary()
          for service in summary['services']:
              if service['name'] == service_name:
                  return service['guid']
  
          raise ValueError("No service with name '%s' found." % (service_name))
docs: Returns the GUID for the service instance with
          the given name.