@Override public boolean remove(Object o) {
      if (!(o instanceof Entry)) {
        return false;
      }

      Node<K, V> node = findByEntry((Entry<?, ?>) o);
      if (node == null) {
        return false;
      }
      removeInternal(node, true);
      return true;
    }
This stack is a singly linked list, linked by the 'parent' field.
lottie/src/main/java/com/airbnb/lottie/parser/moshi/LinkedHashTreeMap.java