This bug appears on both 0.9.3 and the latest development version (from Github). I also have an installation of 0.5.8, which does not exhibit the bug.
To reproduce, simply run the following in the Python interpreter:
>>> from sqlalchemy.orm.interfaces import * Traceback (most recent call last): File "<stdin>", line 1, in <module> AttributeError: 'module' object has no attribute 'ExtensionOption'
Due to the simplicity of the bug, I wasn't sure if I was just missing something obvious, but a quick search didn't lead to any relevant information on ExtensionOption.