Most of the tutorial in the README works as written, but it's never clear why path is introduced mypkg. But at the end of the tutorial is this:
the underlying modules are also accessible, for example:
from mypkg.sub import Class1
sub does not appear in the sample code, and this sample line fails for a reader following along.
However, the code in example/mypkg/__init__.py does introduce sub and no longer uses path. This is a better example!
It would be an improvement if that example file were merged into the README, and the corresponding usage excerpt were updated to match.