def handle_read(self):
        self.read_events()
        self.process_events()
adds stages with no incomplete predecessors to the runnable queue
dataset/ETHPy150Open seb-m/pyinotify/python2/pyinotify.py/AsyncNotifier.handle_read--crossover with--dataset/ETHPy150Open Mouse-Imaging-Centre/pydpiper/pydpiper/pipeline.py/Pipeline.computeGraphHeads