[ZODB-Dev] ImportError: cannot import name Interface

[Tim Peters]

[Diez Roggisch, gets a Mystery ImportError on Interface in 3.3b2]

[Christian Robottom Reis]
> 9 out of 10 ZODB-dev subscribers bet you have PythonCAD installed <wink>.
> ...
> The only workaround I know of currently is removing PythonCAD, but (hey
> Art!) this problem was discussed earlier and a solution should be in the
> queue.

Whatever that is, I would like a different workaround for the next ZODB 3.3.
I've never seen this before, so am ill-prepared to test it.  So if one of
you would like to keep PythonCAD installed, and also ZODB 3.3b2, please try
this and let me know whether it works:

    get BTrees/__init__.py into an editor
    delete the entire content
    save the file
    try again

IOW, I don't believe that anything BTrees/__init__.py tries to do is
necessary anymore (in ZODB 3.3), and that's the only ZODB file normally
imported that references Interface (at top level; other files reference
zope.interface.Interface instead; and even BTrees/__init__.py didn't expect
to *succeed* importing Interface; long story, for which see Zope 2's and the
Python Type-SIG's histories <wink>).