ExtractVariables: OR'ing XPath to select an element

Google Cloud Apigee
1

In the ExtractVariables Policy, is it valid to have multiple elements under the element. For example

        <Variable name="orderCancelInXml" type="nodeset">
            <XPath>//orderCancelIn/*</XPath>
            <XPath>/*</XPath>            
        </Variable>

I have a case where either orderCancelIn exists in the XML or it does not. If it does not, then I want to select everything under the root.

This seems to work, but I’m wondering what the best practice is.