code: func (actor Actor) ResetOrganizationDefaultIsolationSegment(orgGUID string) (Warnings, error) {
  	_, apiWarnings, err := actor.CloudControllerClient.UpdateOrganizationDefaultIsolationSegmentRelationship(orgGUID, "")
  	return Warnings(apiWarnings), err
  }
docs: // ResetOrganizationDefaultIsolationSegment resets the default isolation segment fon
  // an organization.