It's typically used either for additional documentation or for type inference (like for IDEs, static analysis). Only the fact that you can annotate parameters/r

It's typically used either for additional documentation or for type inference (like for IDEs, static analysis). Only the fact that you can annotate parameters/return types is implemented. This was basically done to see how annotations would evolve in community use. http://www.python.org/dev/peps/pep-3107/#use-cases http://www.python.org/dev/peps/pep-3107/#use-cases >> Despite yet more discussion, it was decided not to standardize a mechanism for annotation interoperability. Standardizing interoperability conventions at this point would be premature. We would rather let these conventions develop organically, based on real-world usage and necessity, than try to force all users into some contrived scheme.