code: func StackWrite(ctx formatter.Context, stacks []*Stack) error {
  	render := func(format func(subContext formatter.SubContext) error) error {
  		for _, stack := range stacks {
  			if err := format(&stackContext{s: stack}); err != nil {
  				return err
  			}
  		}
  		return nil
  	}
  	return ctx.Write(newStackContext(), render)
  }
docs: // StackWrite writes formatted stacks using the Context