code: func (s *RepositoriesService) ListByOrg(ctx context.Context, org string, opt *RepositoryListByOrgOptions) ([]*Repository, *Response, error) {
  	u := fmt.Sprintf("orgs/%v/repos", org)
  	u, err := addOptions(u, opt)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	req, err := s.client.NewRequest("GET", u, nil)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	// TODO: remove custom Accept headers when APIs fully launch.
  	acceptHeaders := []string{mediaTypeTopicsPreview}
  	req.Header.Set("Accept", strings.Join(acceptHeaders, ", "))
  
  	var repos []*Repository
  	resp, err := s.client.Do(ctx, req, &repos)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return repos, resp, nil
  }
docs: // ListByOrg lists the repositories for an organization.
  //
  // GitHub API docs: https://developer.github.com/v3/repos/#list-organization-repositories