private @Nullable Object getSlowData(@NotNull String dataId) {
      if (!CommonDataKeys.PSI_ELEMENT.is(dataId)) return null;
      TaintNode[] selectedNodes = getSelectedNodes(TaintNode.class, null);
      if (selectedNodes.length != 1) return null;
      return selectedNodes[0].getRef();
    }
private @Nullable Object getSlowData(@NotNull String dataId)