OpenImmo/src/main/java/org/openestate/io/openimmo/converters/OpenImmo_1_2_0.java
protected void upgradeMieteinnahmenElements(Document doc) throws JaxenException {
        List nodes = XmlUtils.newXPath(
                "/io:openimmo/io:anbieter/io:immobilie/io:preise/io:mieteinnahmen_ist |" +
                        "/io:openimmo/io:anbieter/io:immobilie/io:preise/io:mieteinnahmen_soll",
                doc).selectNodes(doc);
        for (Object item : nodes) {
            Element node = (Element) item;
            node.setAttribute("periode", "JAHR");
        }
    }
protected void upgradeMieteinnahmenElements(Document doc) throws JaxenException {
        List nodes = XmlUtils.newXPath(
                "/io:openimmo/io:anbieter/io:immobilie/io:preise/io:mieteinnahmen_ist |" +
                        "/io:openimmo/io:anbieter/io:immobilie/io:preise/io:mieteinnahmen_soll",
                doc).selectNodes(doc);
        for (Object item : nodes) {
            Element node = (Element) item;
            node.setAttribute("periode", "JAHR");
        }
    }
Upgrade &lt;mieteinnahmen_ist&gt;, &lt;mieteinnahmen_soll&gt; elements
to OpenImmo 1.2.0.
<p>
The "periode" attribute with the value "JAHR" is added to any
&lt;mieteinnahmen_ist&gt; and &lt;mieteinnahmen_soll&gt; elements.

@param doc OpenImmo document in version 1.1
@throws JaxenException if xpath evaluation failed