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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def set_consistent(self, consistent_config):
 """ Indicates that the stream is the start of a consistent region. Args: consistent_config(consistent.ConsistentRegionConfig):
 the configuration of the consistent region. Returns: Stream: Returns this stream. .. versionadded:: 1.11 """


        # add job control plane if needed
        self.topology._add_job_control_plane()
        self.oport.operator.consistent(consistent_config)
        return self._make_placeable()