when plotting a color bar with a plot in matplotlib, the color bar
gets treated internally as Axes.
With two main plots, each of which comes with a color bar, one structurally gets
(that is, a Figure has for childres Axes). To find out which one of
those is a color bar, I basically inspect their children an look for
Arrays with shape (256,), which is what color bars look like. That's
ugly of course, but it kind of works(tm).
I'm having problems, though, with associating color bars with the
specific plot. Can I rely on the rule that an Axes -- if it has a
color bar --, is immediately followed by the corresponding (color bar)
Axes environment? Are there any other properties I could check to
identify color bars? (Tried get_label to no avail.)