Error cell [14] issubclass() arg 1 must be a class

[DanD364]

Hello,

Thank you very much for this amazing work. I am trying to understand a bit better differentiable physics for fluid dynamics and this would help me a lot.

However when I am trying to run your code there is an error on cell 14 that I was unable to solve. Maybe due to an update of HfArgumentParser? Everything ran well on the previous cells (except for a small typo on cell 5 where there were some spaces after the '%' sign but that's straight forward to fix)

Do you have an idea on how to fix it and run your code?

Thank you very much