Q:

Customized y label(s) using matlibplot

Hopefully this is a simple question. I am trying to create a control chart and I was wondering if there is a way to add Upper and Lower control limit label such as UCL, LCL at certain location on the charts y label (see screenshot).
Below is an except of my code:
def control_chart(x,y,fig_num=1, sigma=1, title="", X_MIN=None,
            X_MAX=None, Y_MIN=None, Y_MAX=None,
            xlabel="", ylabel=""):
    ...

    fig1 = plt.figure(fig_num)

    ...

    plt.axis([X_MIN, X_MAX,Y_MIN,Y_MAX])
    plt.plot(week, y, "black")
    plt.plot(week, [x_bar for _ in range(len(x))], "red")
    plt.plot(week, [UCL for _ in range(len(x))],'r-.', lw=2)
    plt.plot(week, [LCL for _ in range(len(x))],'r-.',lw=2)
    plt.plot(o1,o2,'ro')    
    plt.title(title)
    plt.xlabel(xlabel)
    plt.ylabel(ylabel)

A:

Does this work? 
plt.text(X_MAX, UCL, "UCL")` 

I can't test it because you haven't provided data in your code, so I can't run it.

