TypeError: Class advice impossible in Python3. Use the @implementer class decorator instead.

Hi,
I see to run into an error trying to create a Klein process. When using python 3.5.1, twisted 16.2.0 and Klein 0.2.3 (or 0.2.1) I receive a TypeError: Class advice impossible in Python3. Use the @implementer class decorator instead. on a rather basic bit of code:

from klein import Klein
from twisted import inlineCallbacks, returnValue

app = Klein()

@app.route("/")
@inlineCallbacks
def hello(request):
    returnValue("hello")

app.run("0.0.0.0", 8080)

I also import a separate module using umongo with txmongo, but I don't beleive those should collide.

This is the stack trace I receive:

raceback (most recent call last):
  File "/opt/src/auth.py", line 3, in <module>
    from klein import Klein
  File "/usr/local/lib/python3.5/site-packages/klein/__init__.py", line 1, in <module>
    from klein.app import Klein, run, route, resource
  File "/usr/local/lib/python3.5/site-packages/klein/app.py", line 32, in <module>
    class KleinRequest(object):
  File "/usr/local/lib/python3.5/site-packages/klein/app.py", line 33, in KleinRequest
    implements(IKleinRequest)
  File "/usr/local/lib/python3.5/site-packages/zope/interface/declarations.py", line 412, in implements
    raise TypeError(_ADVICE_ERROR % 'implementer')
TypeError: Class advice impossible in Python3.  Use the @implementer class decorator instead.

Start in klein/app.py at KleinRequest and the implements(IKleinRequest) call shown in the Python 3.5 stack trace. Reproduce the import with the provided Klein example and verify that Klein loads and the example runs without the TypeError.