root(keystone_admin)@controller1:~/cloudkitty$ cloudkitty-api --config-file /etc/cloudkitty/cloudkitty.conf
Traceback (most recent call last):
  File "/usr/local/bin/cloudkitty-api", line 6, in <module>
    from cloudkitty.cli.api import main
  File "/usr/local/lib/python2.7/dist-packages/cloudkitty/cli/api.py", line 18, in <module>
    from cloudkitty.api import app
  File "/usr/local/lib/python2.7/dist-packages/cloudkitty/api/app.py", line 27, in <module>
    from cloudkitty.api import config as api_config
  File "/usr/local/lib/python2.7/dist-packages/cloudkitty/api/config.py", line 12, in <module>
    from cloudkitty import config  # noqa
  File "/usr/local/lib/python2.7/dist-packages/cloudkitty/config.py", line 20, in <module>
    from oslo_messaging import opts  # noqa
  File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/__init__.py", line 17, in <module>
    from .notify import *
  File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/notify/__init__.py", line 27, in <module>
    from .notifier import *
  File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/notify/notifier.py", line 29, in <module>
    from oslo_messaging import serializer as msg_serializer
  File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/serializer.py", line 67, in <module>
    @removals.removed_class("RequestContextSerializer",
AttributeError: 'module' object has no attribute 'removed_class'