xmlslurper_add_sibling.groovy

import groovy.util.XmlSlurper

def xml = new XmlSlurper().parseText('''
<issues>
    <issue>
        <id>1</id>
        <priority>1</priority>
    </issue>
    <issue>
        <id>2</id>
        <priority>2</priority>
    </issue>
</issues>
''')
def p = '1'
def priorityIssue = xml.'**'.find { issue ->
    issue.priority.text() == p
}

xml.issue[0].replaceNode { node ->
   mkp.yield(node)
   hermano('lamano')
}

println xml.children()*.name()
println xml.find { it.name() == 'hermano' }

groovy.xml.XmlUtil.serialize( xml )