code: def gradient_line(xs, ys, colormap_name='jet', ax=None):
    '''Plot a 2-d line with a gradient representing ordering.
    See http://stackoverflow.com/q/8500700/10601 for details.'''
    if ax is None:
      ax = plt.gca()
    cm = plt.get_cmap(colormap_name)
    npts = len(xs)-1
    colors = cm(np.linspace(0, 1, num=npts))
    if hasattr(ax, 'set_prop_cycle'):
      ax.set_prop_cycle(color=colors)
    else:
      ax.set_color_cycle(colors)
    for i in range(npts):
      ax.plot(xs[i:i+2],ys[i:i+2])
    return plt.shof gradient_line(xs, ys, colormap_name='jet', ax=None):
    '''Plot a 2-d line with a gradient representing ordering.
    See http://stackoverflow.com/q/8500700/10601 for details.'''
    if ax is None:
      ax = plt.gca()
    cm = plt.get_cmap(colormap_name)
    npts = len(xs)-1
    colors = cm(np.linspace(0, 1, num=npts))
    if hasattr(ax, 'set_prop_cycle'):
      ax.set_prop_cycle(color=colors)
    else:
      ax.set_color_cycle(colors)
    for i in range(npts):
      ax.plot(xs[i:i+2],ys[i:i+2])
    return plt.show
docs: Plot a 2-d line with a gradient representing ordering.
    See http://stackoverflow.com/q/8500700/10601 for details.