ggplot function to add text just below legend

Question

In R I want to make a function which takes an ggplot object and some text and returns and ggplot object by adds text just below the legend (in the right side of the plot, w

Answer 1

Another easy possibility is to use a caption:

myplot = ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, color=Species)) + 
           geom_line() +
           labs(caption = "Mean of Sepal.Width = 3.05")

It's not really right below the legend, though: