Stop using chumpy

[lucasjinreal]

For python >= 3.11 chumpy would not work anymore.

chumpy/ch.py", line 1203, in _depends_on
want_out = 'out' in inspect.getargspec(func).args
^^^^^^^^^^^^^^^^^^
AttributeError: module 'inspect' has no attribute 'getargspec'. Did you mean: 'getargs'?

Any chumpy is not longer maintained.