code: def _darkest(self):
          
          min, n = (1.0, 1.0, 1.0), 3.0
          for clr in self:
              if clr.r + clr.g + clr.b < n:
                  min, n = clr, clr.r + clr.g + clr.b
  
          return min
docs: Returns the darkest color from the list.
  
          Knowing the contrast between a light and a dark swatch
          can help us decide how to display readable typography.