code: func getBanner(c context.Context, b *buildbot.Build) *ui.LogoBanner {
  	osLogo := func() *ui.Logo {
  		result := &ui.Logo{}
  		switch b.OSFamily {
  		case "windows":
  			result.LogoBase = ui.Windows
  		case "Darwin":
  			result.LogoBase = ui.OSX
  		case "Debian":
  			result.LogoBase = ui.Ubuntu
  		default:
  			return nil
  		}
  		result.Subtitle = b.OSVersion
  		return result
  	}()
  	if osLogo != nil {
  		return &ui.LogoBanner{
  			OS: []ui.Logo{*osLogo},
  		}
  	}
  	return nil
  }
docs: // getBanner parses the OS information from the build and maybe returns a banner.