code: public boolean putMany(int key, Collection<Integer> values) {
          // Short circuit when adding empty values to avoid adding a key with an
          // empty mapping
          if (values.isEmpty())
              return false;
          IntSet vals = map.get(key);
          if (vals == null) {
              vals = new TroveIntSet(values.size());
              map.put(key, vals);
          }
          int oldSize = vals.size();
          boolean added = vals.addAll(values);
          range += (vals.size() - oldSize);
          return added;
      }
docs: {@inheritDoc}