Legend text size not changing

If I set a legend text size, it doesn't appear to be affected.

import plotnine as p9
from  plotnine.data import faithful
from plotnine import ggplot, aes
import matplotlib.pyplot as plt

p9.options.figure_size = (15,15)
g = (ggplot(data=faithful)
     + p9.geom_density_2d(aes(x='eruptions', y='waiting', color='..level..'))
     + p9.theme(legend_text=p9.element_text(size=90))
)
g.save('geyser.png')