Tests fail for python-3.6

[toabctl]

$ tox -epy36
py36 create: /home/tom/devel/Zake/.tox/py36
py36 installdeps: -r/home/tom/devel/Zake/test-requirements.txt
py36 develop-inst: /home/tom/devel/Zake
py36 installed: extras==1.0.0,fixtures==3.0.0,flake8==3.4.1,kazoo==2.4.0,linecache2==1.0.0,mccabe==0.6.1,nose==1.3.7,pbr==3.1.1,pycodestyle==2.3.1,pyflakes==1.5.0,python-mimeparse==1.6.0,six==1.10.0,testtools==2.3.0,traceback2==1.4.0,unittest2==1.1.0,-e git+https://github.com/yahoo/Zake.git@5947970bfec16826c8b362e1a23e55fc0b883748#egg=zake
py36 runtests: PYTHONHASHSEED='2797179808'
py36 runtests: commands[0] | nosetests
...F.........................................
======================================================================
FAIL: zake.tests.test_client.TestClient.test_child_watch_no_create
----------------------------------------------------------------------
testtools.testresult.real._StringException: Traceback (most recent call last):
  File "/home/tom/devel/Zake/zake/tests/test_client.py", line 469, in test_child_watch_no_create
    self.client, "/b", cb)
  File "/home/tom/devel/Zake/.tox/py36/lib/python3.6/site-packages/testtools/testcase.py", line 485, in assertRaises
    self.assertThat(our_callable, matcher)
  File "/home/tom/devel/Zake/.tox/py36/lib/python3.6/site-packages/testtools/testcase.py", line 498, in assertThat
    raise mismatch_error
testtools.matchers._impl.MismatchError: <class 'kazoo.recipe.watchers.ChildrenWatch'> returned <kazoo.recipe.watchers.ChildrenWatch object at 0x7f834f79a8d0>


----------------------------------------------------------------------
Ran 45 tests in 0.143s

FAILED (failures=1)
ERROR: InvocationError: '/home/tom/devel/Zake/.tox/py36/bin/nosetests'
_________________________________________________________________________________________________________________ summary __________________________________________________________________________________________________________________
ERROR:   py36: commands failed