code: private Span[] setProbs(final Span[] spans) {
      final double[] probs = probs(spans);
      if (probs != null) {
  
        for (int i = 0; i < probs.length; i++) {
          final double prob = probs[i];
          spans[i] = new Span(spans[i], prob);
        }
      }
      return spans;
    }
docs: sets the probs for the spans
  
  @param spans
  @return