void registerParent(@Nullable WrapImpl parent) {
    if (parent == this) return;
    if (parent == null) return;
    if (parent.isChildOf(this, null, new FormatterIterationMonitor<>(MAX_IS_CHILD_OF_CALCULATION_ITERATIONS, true))) return;
    if (myParents == emptyParentsSet) myParents = new HashSet<>(5);
    myParents.add(parent);
  }
void registerParent(@Nullable WrapImpl parent)