matplotlib-charts example warns about nr of figures opened

[bigfooted]

The matplotlib example 05_charts/Matplotlib/00_matplotlib-charts.py will replot the figure when you resize the window. When you resize it for a couple of seconds, you will get the message:

~/trame/examples/05_charts/Matplotlib/00_matplotlib-charts.py:45: RuntimeWarning: More than 20 figures have been opened. Figures created through the pyplot interface (matplotlib.pyplot.figure) are retained until explicitly closed and may consume too much memory. (To control this warning, see the rcParam figure.max_open_warning). Consider using matplotlib.pyplot.close(). fig, ax = plt.subplots(**figure_size())

I just placed a
plt.close('all')
before the fig,ax=plt.subplots() line and I did not get this message anymore. I guess it could indeed be an issue when you let it run for a while?

[jourdain]

Do you mind doing a PR to update the example?