[Numpy-discussion] NotImplementedType should be an exception

[Travis E. Oliphant]

Charles R Harris wrote:
> Shouldn't this raise an NotImplementedError exception?
>
> In [7]: type(remainder(complex192(1), complex192(1)))
> Out[7]: <type 'NotImplementedType'>
I'm not sure if it is relevant in this case but we do need to keep in 
mind that Python uses the NotImplementedType as a signal to hand off the 
calculation to the other object in a binary operation.

If we change this here we may affect that behavior, unintentionally.

-Travis