@Deprecated(forRemoval = true)
  public static @Nullable <T> DataNode<T> find(
    @NotNull DataNode<?> node,
    @NotNull Key<T> key,
    @Nullable BooleanFunction<? super DataNode<T>> predicate
  ) {
    if (predicate == null) {
      return findChild(node, key, null);
    }
    else {
      return findChild(node, key, it -> predicate.fun(it));
    }
  }
@Deprecated(forRemoval = true)
  public static @Nullable <T> DataNode<T> find(
    @NotNull DataNode<?> node,
    @NotNull Key<T> key,
    @Nullable BooleanFunction<? super DataNode<T>> predicate
  )