code: def triad(clr, angle=120):
      
      clr = color(clr)
      colors = colorlist(clr)
      colors.append(clr.rotate_ryb(angle).lighten(0.1))
      colors.append(clr.rotate_ryb(-angle).lighten(0.1))
  
      return colors
docs: Returns a triad of colors.
  
      The triad is made up of this color and two other colors
      that together make up an equilateral triangle on
      the artistic color wheel.