Not very Pythonic

  for i in range(len(records)):
    scores[i] = score(records[i])

  for i, record in enumerate(records):
    scores[i] = score(record)

  scores = [score(record) for record in records]

Sure those are good designs... But Lucen is not about "here's a nicer way to write loops," it's "you shouldn't have to touch the loop you already have."..... showing Lucen parallelize the ugly version is the point.