Python: Function to plot an nice error bar with Matplotlib

gistfile1.py

def errorfill(x, y, yerr, color=None, alpha_fill=0.3, ax=None):
  # Plot the standart error bar stolen from http://tonysyu.github.com/plotting-error-bars.html
  ax = ax if ax is not None else plt.gca()
  if color is None:
    color = ax._get_lines.color_cycle.next()
    if np.isscalar(yerr) or len(yerr) == len(y):
      ymin = y - yerr
      ymax = y + yerr
    elif len(yerr) == 2:
      ymin, ymax = yerr
    ax.plot(x, y, color=color)
    ax.fill_between(x, ymax, ymin, color=color, alpha=alpha_fill)