code: func (actor Actor) CreateIsolationSegmentByName(isolationSegment IsolationSegment) (Warnings, error) {
  	_, warnings, err := actor.CloudControllerClient.CreateIsolationSegment(ccv3.IsolationSegment(isolationSegment))
  	if _, ok := err.(ccerror.UnprocessableEntityError); ok {
  		return Warnings(warnings), actionerror.IsolationSegmentAlreadyExistsError{Name: isolationSegment.Name}
  	}
  	return Warnings(warnings), err
  }
docs: // CreateIsolationSegmentByName creates a given isolation segment.