code: def colors(self, brew=None, range_=None):
          
          if brew:
              self.scales['color'].range = brews[brew]
          elif range_:
              self.scales['color'].range = range_
          return self
docs: Convenience method for adding color brewer scales to charts with a
          color scale, such as stacked or grouped bars.
  
          See the colors here: http://colorbrewer2.org/
  
          Or here: http://bl.ocks.org/mbostock/5577023
  
          This assumes that a 'color' scale exists on your chart.
  
          Parameters
          ----------
          brew: string, default None
              Color brewer scheme (BuGn, YlOrRd, etc)
          range: list, default None
              List of colors. Ex: ['#ac4142', '#d28445', '#f4bf75']