code: function nodeIsRenderedByOtherInstance(container) {
    var rootEl = getReactRootElementInContainer(container);
    return !!(rootEl && isReactNode(rootEl) && !ReactDOMComponentTree.getInstanceFromNode(rootEl));
  }
docs: True if the supplied DOM node is a React DOM element and
  it has been rendered by another copy of React.
  
  @param {?DOMElement} node The candidate DOM node.
  @return {boolean} True if the DOM has been rendered by another copy of React
  @internal