File "/usr/local/lib/python2.7/dist-packages/canaryd/plugin.py", line 364, in get_plugin_state
state = plugin.get_state(settings)
File "/usr/local/lib/python2.7/dist-packages/canaryd/plugins/containers.py", line 67, in get_state
containers.update(func(timeout=timeout))
File "/usr/local/lib/python2.7/dist-packages/canaryd/plugins/containers_util.py", line 26, in get_docker_containers
'command': ' '.join(container['Config']['Cmd']),
TypeError: can only join an iterable```