from novaclient import client
File "/usr/local/lib/python2.7/dist-packages/novaclient/__init__.py", line 15, in <module>
import pbr.version
ImportError: No module named version

loader = loading.get_plugin_loader('password')
    auth = loader.load_from_options(auth_url=auth_url, username=username, password=password, project_name=tenant_name)
    sess = session.Session(auth=auth)
    nova = client.Client('2', session=sess) #API version and session