Hi,
First of all, thanks a lot for this amazing toolbox!

I think, I found a bug, or a suggestion for improvement, when running the prey example:
https://python-control.readthedocs.io/en/0.9.3.post2/iosys.html#example

When I run the code of the prey example, in particular the linearization,
lin_predprey = ct.linearize(io_predprey, xeq, 0)
I get the following error
ValueError: setting an array element with a sequence. The requested array has an inhomogeneous shape after 1 dimensions. The detected shape was (2,) + inhomogeneous part.

After analyzing the code, I think the origin of the error is that in predprey_rhs() dH is of type numpy arrary, while dL is not.

I think others ones are much deeper in the code than me. That is why I post this topic instead of a pull request.

Maybe a type check with dummy input/output data already solves these kind of issues when initializing the constructor. I think such a feature could save people some time.

Best,
codeFighter2022

Python: 3.810
Control: 0.9.3.post2
I installed the toolbox via pip