def start(self):
        self.thread = threading.currentThread()
        sys.settrace(self._trace)
        return self._trace
Keeps an internal reference to slice_ctx.
dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/coverage/collector.py/PyTracer.start--crossover with--dataset/ETHPy150Open GoogleCloudPlatform/appengine-mapreduce/python/src/mapreduce/api/map_job/output_writer.py/OutputWriter.begin_slice