# second version: we use GeneratorExit to stop
# no more need for a method, hence no need for a class


def accumulator(batch_size):
    try:
        while True:
            batch = []
            for c in range(batch_size):
                received = yield
                batch.append(received)
            print('flush', batch)
    except GeneratorExit:
        print('flush', batch)


it = accumulator(batch_size=3)

next(it)  # prime it

for i in range(10):
    it.send(i)

it.close()   # raises GeneratorExit inside the generator