public static @NotNull List<NotificationParentGroupBean> getChildren(@NotNull NotificationParentGroupBean parent) {
    prepareInfo();
    List<NotificationParentGroupBean> children = myChildren.get(parent);
    return children == null ? Collections.emptyList() : children;
  }
public static @NotNull List<NotificationParentGroupBean> getChildren(@NotNull NotificationParentGroupBean parent)