def __init__(self, cache=None, blocking=False):
    # Cache of CloudWorkflowStep protos generated while the runner
    # "executes" a pipeline.
    self._cache = cache if cache != None else PValueCache()
    self.blocking = blocking
    self.result = None
    self._unique_step_id = 0
dataset/ETHPy150Open GoogleCloudPlatform/DataflowPythonSDK/google/cloud/dataflow/runners/dataflow_runner.py/DataflowPipelineRunner.__init__/operator `is not` -> `!=`