Submission 77

Uncaught exception while running Docker Compose:
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/duckietown_challenges-3.0.27-py2.7.egg/duckietown_challenges/runner.py", line 356, in run
    pruned = client.networks.prune()
  File "/usr/local/lib/python2.7/dist-packages/docker/models/networks.py", line 214, in prune
    return self.client.api.prune_networks(filters=filters)
  File "/usr/local/lib/python2.7/dist-packages/docker/utils/decorators.py", line 34, in wrapper
    return f(self, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/docker/api/network.py", line 174, in prune_networks
    return self._result(self._post(url, params=params), True)
  File "/usr/local/lib/python2.7/dist-packages/docker/api/client.py", line 235, in _result
    self._raise_for_status(response)
  File "/usr/local/lib/python2.7/dist-packages/docker/api/client.py", line 231, in _raise_for_status
    raise create_api_error_from_http_exception(e)
  File "/usr/local/lib/python2.7/dist-packages/docker/errors.py", line 31, in create_api_error_from_http_exception
    raise cls(e, response=response, explanation=explanation)
APIError: 409 Client Error: Conflict ("a prune operation is already running")