code: func NewCell(rune rune, args ...interface{}) Cell {
  	style := StyleClear
  	if len(args) == 1 {
  		style = args[0].(Style)
  	}
  	return Cell{
  		Rune:  rune,
  		Style: style,
  	}
  }
docs: // NewCell takes 1 to 2 arguments
  // 1st argument = rune
  // 2nd argument = optional style