public static void assertNodeNotSame(Node node1, Node node2) {
    if (node1 == node2) {
      throw new IllegalArgumentException(
          "Node can only have one parent. Please use two different Node object instances.");
    }
  }
Makes sure the addresses of two nodes aren't the same. Is used to check {@link Node}s passed in
by an API user. Since every {@link Node} can only be associated with one parent, if two {@link
Node}s are being passed in, there is a certain risk the API user may pass in the same node
twice, which will result in the node only being rendered in the GUI once.

@param node1 first node to check
@param node2 second node to check
@throws IllegalArgumentException if node1 == node2
workbenchfx-core/src/main/java/com/dlsc/workbenchfx/util/WorkbenchUtils.java