Draw horizontal p-value comparison bars in barplots

draw_bars

def drawBars(ax, s, ypos, xpos = [0.5,1.5], tick_height = 0.02, fontsize=12, fontcolor="black"):
    ypos = ypos/float(ax.get_ylim()[1]) + tick_height
    
    trans = transforms.blended_transform_factory(ax.transData, ax.transAxes)
    l = Line2D([xpos[0], xpos[0], xpos[1], xpos[1]],[ypos, ypos+tick_height, ypos+tick_height, ypos], lw=1.5, c="k", transform=trans)
    ax.text(xpos[0] + ((xpos[1]-xpos[0])/2.), ypos + (tick_height*1.5), s=s, ha= "center", va="bottom", fontsize=fontsize, color=fontcolor, transform=trans)
    ax.add_line(l)