def grouper(results):
 while True:
 key = yield
 results[key] = yield from averager()
def main(data):
 results = {}
 group = grouper(results)
 next(group)
 for key, values in data.items():
 group.send(key)
 for value in values:
 group.send(value)
 group.send(None)
 group.close() # just to highlight that grouper is still an active generator
 report(results)