$ git clone git@github.com:GoogleCloudPlatform/gcloud
$ cd gcloud
$ tox -e system-tests --notest
$ .tox/system-tests/bin/python

>>> from google.logging.v2.config_service_v2_api import ConfigServiceV2Api
>>> from gcloud.logging._gax import _SinksAPI
>>> from gcloud.logging import Client
>>> client = Client()
>>> client._sinks_api = _SinksAPI(ConfigServiceV2Api())
>>> sink = client.sink('gcloud-issue-1890-sink', 'logName=gcloud-issue-1890',
...                    'storage.googleapis.com/your-bucket-name')
>>> sink.exists()
False
>>> sink.create()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/tseaver/projects/agendaless/Google/src/gcloud-python/gcloud/logging/sink.py", line 117, in create
    self.project, self.name, self.filter_, self.destination)
  File "/home/tseaver/projects/agendaless/Google/src/gcloud-python/gcloud/logging/_gax.py", line 188, in sink_create
    self._gax_api.create_sink(parent, sink_pb, options)
  File "/home/tseaver/projects/agendaless/Google/src/gcloud-python/.tox/py27/lib/python2.7/site-packages/google/logging/v2/config_service_v2_api.py", line 302, in create_sink
    sink=sink)
  File "/home/tseaver/projects/agendaless/Google/src/gcloud-python/.tox/py27/lib/python2.7/site-packages/google/protobuf/internal/python_message.py", line 496, in init
    field = _GetFieldByName(message_descriptor, field_name)
  File "/home/tseaver/projects/agendaless/Google/src/gcloud-python/.tox/py27/lib/python2.7/site-packages/google/protobuf/internal/python_message.py", line 560, in _GetFieldByName
    (message_descriptor.name, field_name))
ValueError: Protocol message CreateSinkRequest has no "parent" field.