AttributeError: 'NoneType' object has no attribute 'get_view_interval'

[wangy8989]

When I run demo.grcar_demo(), I got this error, even it is able to calculate and plot.
Could anyone help with this? Thanks!

[silvioba]

I had the same issue. I suggest changing line 62 of utils.py to
pyplot.clabel(contours)
This fixes the problem for me