Omit blank figure

[jakubno]

Description

There are some edge cases, when the code would generate 2 charts and one of them blank. We will simply omit blank charts

From matplotlib docs:

Notes

Saving figures to file and showing a window at the same time

If you want an image file as well as a user interface window, use pyplot.savefig before pyplot.show. At the end of (a blocking) show() the figure is closed and thus unregistered from pyplot. Calling pyplot.savefig afterwards would save a new and thus empty figure. This limitation of command order does not apply if the show is non-blocking or if you keep a reference to the figure and use Figure.savefig.