code: def create_contours_obj(canvas, contour_groups, colors=None, **kwargs):
      
      if colors is None:
          colors = ['black']
      Polygon = canvas.get_draw_class('polygon')
      Compound = canvas.get_draw_class('compoundobject')
      objs = [Polygon(contour, color=colors[i % len(colors)], **kwargs)
              for i, contours in enumerate(contour_groups)
              for n, contour in enumerate(contours)
              ]
      contours_obj = Compound(*objs)
      return contours_obj
docs: Create and return a compound object for ginga `canvas`, consisting
      of a number of contour polygons.  `contour_groups` is a list of
      numpy arrays of points representing polygons, such as returned by
      calc_contours() or get_contours().
      `colors` (if provided) is a list of colors for each polygon.
      Any other keyword parameters are passed on to the Polygon class.