code: def add_density_option_group(parser):
      
      density_group = parser.add_argument_group("Options for configuring the "
                                                "contours and density color map")
  
      density_group.add_argument(
          "--density-cmap", type=str, default='viridis',
          help="Specify the colormap to use for the density. "
               "Default is viridis.")
      density_group.add_argument(
          "--contour-color", type=str, default=None,
          help="Specify the color to use for the contour lines. Default is "
               "white for density plots and black for scatter plots.")
      density_group.add_argument(
          '--use-kombine-kde', default=False, action="store_true",
          help="Use kombine's KDE for determining contours. "
               "Default is to use scipy's gaussian_kde.")
  
      return density_group
docs: Adds the options needed to configure contours and density colour map.
  
      Parameters
      ----------
      parser : object
          ArgumentParser instance.