如何在mule中从xml中选择前4个子标签

//*[position() <= 4]

<mule xmlns:ee="http://www.mulesoft.org/schema/mule/ee/core"
    xmlns:xpath="http://www.mulesoft.org/schema/mule/xpath"
    xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
    xmlns="http://www.mulesoft.org/schema/mule/core"
    xsi:schemaLocation="
        http://www.mulesoft.org/schema/mule/ee/core http://www.mulesoft.org/schema/mule/ee/core/current/mule-ee.xsd
        http://www.mulesoft.org/schema/mule/xpath http://www.mulesoft.org/schema/mule/xpath/current/mule-xpath.xsd
        http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd">
        
    <xpath:config name="XPath_Config" doc:name="XPath Config"/>
    
    <flow name="XPath_Selection_Flow">
        <http:listener config-ref="HTTP_Listener_Configuration" path="/" doc:name="HTTP"/>
        <set-payload value="&lt;root&gt;&lt;child1&gt;Value 1&lt;/child1&gt;&lt;child2&gt;Value 2&lt;/child2&gt;&lt;child3&gt;Value 3&lt;/child3&gt;&lt;child4&gt;Value 4&lt;/child4&gt;&lt;child5&gt;Value 5&lt;/child5&gt;&lt;/root&gt;" doc:name="Set Payload"/>
        <xpath:select xpath="//*[position() &lt;= 4]" config-ref="XPath_Config" doc:name="XPath Selection"/>
        <logger level="INFO" message="#[payload]" doc:name="Logger"/>
    </flow>
    
</mule>