How can I plot two smoothing splines in the same plot with ggplot?
<p>For example, I have a couple of plots like this:</p>

<pre><code>ggplot(mpg, aes(displ, hwy)) +
geom_point() +
geom_smooth(method = "lm", formula = y ~ splines::bs(x, 3), se = T)
</code></pre>

<p>Is it possible to plot 2 of these kind into the same plot?</p>