How to specify legend position in matplotlib in graph coordinates

Question

I am aware of the bbox_to_anchor keyword and this thread, which very helpfully suggests how to manually place the legend:

How to put the legend out of the plot

Answer 1

In addition to @ImportanceOfBeingErnest's post, I use the following line to add a legend at an absolute position in a plot.

plt.legend(bbox_to_anchor=(1.0,1.0),\
    bbox_transform=plt.gcf().transFigure)

For unknown reasons, bbox_transform=fig.transFigure does not work with me.