weights typechecking will only accept things from pysal.

[ljwolf]

In theory, so long as the object provides the right methods, it should be usable in spreg.

Right now, this poses a problem, since weights objects constructed in a submodule (e.g. libpysal) cannot be used in the independent spreg package.

[ljwolf]

I guess this also includes people who might want to subclass W, like gwr.