code: public boolean remove(Object key, Object value) {
          Set<V> values = map.get(key);
          // If the key was not mapped to any values
          if (values == null)
              return false;
          boolean removed = values.remove(value);
          if (removed)
              range--;
          // if this was the last value mapping for this key, remove the
          // key altogether
          if (values.size() == 0)
              map.remove(key);
          return removed;
      }
docs: {@inheritDoc}