On the pandas dev call this morning we discussed whether to bump the cython
version we are using from 0.29.x to the most recent 3.0 alpha.
The main _new_ point that was made was that we should stick to versions
that are available on conda-forge. The latest there is 0.29.24.
Aside from that, I'll
Would the following be a good use case for what you're discussing?
```
cdef class Base:
cdef __cinit__(self, **kwargs):
for name in self.list_defined_on_subclass:
value = kwargs[name]
setattr(self, name, value)
cpdef copy(self):
kwargs = {name: g
