docs: public void incrementOutcome(A first, B second, double amount) {
      if (!counts.containsKey(first)) {
        counts.put(first, Maps.<B, Double> newHashMap());
      }
      if (!counts.get(first).containsKey(second)) {
        counts.get(first).put(second, 0.0);
      }
      counts.get(first).put(second, amount + counts.get(first).get(second));
      conditionalCounts.put(first, amount + conditionalCounts.get(first));
      totalCount += amount;
    }