[Python-Dev] Fix import errors to have data

[Guido van Rossum]

> An even simpler aproach would be to have a ModuleNotFound error
> that extends ImportError and gets raised if the module can't
> be found.

That wouldn't solve anything, because if foo brokenly tries to import
bar and that raises ModuleNotFound, so will "import foo".

--Guido van Rossum (home page: http://www.python.org/~guido/)