def plot_gradient_fit(t, f, fn, xt, yt, p):
    # f = gradient of fit at points of measurement
    p.plot(xt, yt, lw=3.0, color='black', zorder=1)
    p.scatter(t, f, facecolor='1.0', s=60, color='black', zorder=2, lw=1)
    p.scatter(t, f, facecolor='None', s=60, color='black', zorder=3, lw=1)
    p.scatter(t, fn, facecolor='0.0', s=60, zorder=4, lw=1)
    p.vlines(t, f, fn, zorder=1, lw=2, color='0.5', linestyles='dotted')
    p.set_xlabel('HJD - 2450000 [Days]')
    p.set_ylabel('Normalized gradient (1/days)')
    p.set_title('Measured gradients and fit from J1407')

############################
## TESTING
############################
plot gradient fit
dataset/ETHPy150Open mkenworthy/exorings/exorings.py/plot_gradient_fit