docs: public boolean containsKeyPrefix(String prefix) {
          if (prefix == null) {
              throw new NullPointerException("Prefix key can not be null");
          }
  
          // An empty string is a prefix of everything
          if (prefix.equals("")) {
              return true;
          }
  
          // Find nearest node
          PatriciaNode<V> nearest = findNearestNode(prefix);
  
          // If no nearest node exist, there isn't any prefix match either
          if (nearest == null) {
              return false;
          }
  
          // The nearest is the root, so no match
          if (nearest.getKey() == null) {
              return false;
          }
  
          // Test prefix match
          return nearest.getKey().startsWith(prefix);
      }