def __or__(self, right):
    if isinstance(right, PTransform):
      return ChainedPTransform(self, right)
    else:
      return NotImplemented
Used to compose PTransforms, e.g., ptransform1 | ptransform2.
dataset/ETHPy150Open GoogleCloudPlatform/DataflowPythonSDK/google/cloud/dataflow/transforms/ptransform.py/PTransform.__or__