Colorbar becomes 0 to 1 after colorbar ax.yaxis.set_major_formatter

matplotlib 1.5.3
pip
python 3.4
Ubuntu 14.04

    NO_POWER_FORM = matplotlib.ticker.ScalarFormatter(useMathText=False, useOffset=False)
    NO_POWER_FORM.set_scientific(False)

    colorbar_ax=matplotlib.pyplot.colorbar(ticks=contour_range).ax
    colorbar_ax.set_title(colorbar_zlabel)
    colorbar_ax.yaxis.set_major_formatter(style.NO_POWER_FORM)

