code: def adjust(color, attribute, percent):
      """Adjust an attribute of color by a percent"""
      r, g, b, a, type = parse_color(color)
      r, g, b = hsl_to_rgb(
          *_adjust(rgb_to_hsl(r, g, b), attribute, percent)
      )
      return unparse_color(r, g, b, a, type)
  
file_path: pygal/pygal/colors.py
imports: from __future__ import division
label_desc: Use image node_id 8 for calling a global function with example usage: adjust(color, attribute, percent) and returns: unparse_color