code: func (b *Box) WrapInputHandler(inputHandler func(*tcell.EventKey, func(p Primitive))) func(*tcell.EventKey, func(p Primitive)) {
  	return func(event *tcell.EventKey, setFocus func(p Primitive)) {
  		if b.inputCapture != nil {
  			event = b.inputCapture(event)
  		}
  		if event != nil && inputHandler != nil {
  			inputHandler(event, setFocus)
  		}
  	}
  }
docs: // WrapInputHandler wraps an input handler (see InputHandler()) with the
  // functionality to capture input (see SetInputCapture()) before passing it
  // on to the provided (default) input handler.
  //
  // This is only meant to be used by subclassing primitives.