https://matplotlib.org/gallery/lines_bars_and_markers/fill_between_demo.html
[plotting-error-bars](https://tonysyu.github.io/plotting-error-bars.html)

Plot yerr/xerr as shaded region rather than error bars
**matplotlib.pyplot.fill_betweenx**(y,?x1,?x2=0,?where=None,?step=None,?hold=None,?data=None,?**kwargs)?
