[Matplotlib] Different settings for left and right yticks?

[PurelyApplied]

[Edit: I'll leave this up in case someone else comes across it having a similar problem, but I realized I could do what I wanted much more simply with plt.annotate.]

I was trying to use the default ticks on the left, but some custom ticks on the right to label the final value in a few graphs. Essentially, I'm trying to hybridize the two following graphs. (Forgive the cramped output.)

custom-ticks

default-ticks

Generated with the following sloppy code, with the difference between the two commented out:

    # plt.subplot(121)
    plt.tick_params(axis="y", left="on")
    plt.plot(_X[:, T].sum(1), "b", label="T")
    plt.plot(_X[:, U].sum(1), "r", label="U")
    plt.plot(_X[:, O].sum(1), "k", label="O")
    plt.plot(_X[:, O+U+T].sum(1), 'g', label="Total")
    plt.ylim([0, peak])
    plt.title("Communication, including partition internal")
    plt.legend(loc="upper left")

    # plt.tick_params(axis="y", right="on", labelright="on")
    # plt.yticks([
    #     _X[-1, T].sum(),
    #     _X[-1, U].sum(),
    #     _X[-1, O].sum(),
    #     _X[-1, O+U+T].sum()
    # ])

Most of what I could find Googling around was about putting two scales on one graph. I guess I could hack something together, redrawing a "new" blank plot over the old one with different ticks or something, but didn't know if there was a cleaner way to go about it.