def METHOD_NAME(ds):
    t2 = ds.get_t2df()
    bl_rms = t2['bl_rms']
    hist, bins = np.histogram(bl_rms, bins=250, range=[3,5.5])
    b = (bins[:-1] + bins[1:]) / 2
    plt.plot(b, hist)
    plt.tight_layout()
    plt.show()