Given a plot, how do I return the source code of its SVG representation? (Not save the SVG to disk.)
E.g. this saves to disk:
plot_slope_field(sin(x+y) + cos(x+y), (x,-3,3), (y,-3,3)).save('foo.svg')
I want something like:
plot_slope_field(sin(x+y) + cos(x+y), (x,-3,3), (y,-3,3)).svg_source()
which returns a string containing the source of the SVG.
