new_contents: white, black = '#ffffff', '#000000'
  grey = '#eeeeec', '#d3d7cf', '#babdb6', '#888a85', '#555753', '#2e3436'
  
  red =    '#ef2929', '#cc0000', '#a40000'
  orange = '#fcaf3e', '#f57900', '#ce5c00'
  yellow = '#fce94f', '#edd400', '#c4a000'
  green =  '#8ae234', '#73d216', '#4e9a06'
  blue =   '#729fcf', '#3465a4', '#204a87'
  purple = '#ad7fa8', '#75507b', '#5c3566'
  brown =  '#e9b96e', '#c17d11', '#8f5902'
  
  def color_from_cycle(index):
      cycle = (blue[1], red[1], green[2], orange[1], purple[1], brown[1],
               blue[0], red[0], green[1], orange[0], purple[0], brown[0])
      return cycle[index % len(cycle)]
  
subject: Add the tango color scheme.