What is the XML rule for re-format CN?

<rule>    <description>re-format CN</description>    <conditions>        <and>            <if-class-name mode="nocase" op="equal">User</if-class-name>            <if-op-attr name="urn:ietf:params:scim:schemas:core:2.0:User:userName" op="available"/>          </and>      </conditions>    <actions>        <do-reformat-op-attr name="urn:ietf:params:scim:schemas:core:2.0:User:userName">            <arg-value type="string">                <token-split delimiter="@">                    <token-op-attr name="urn:ietf:params:scim:schemas:core:2.0:User:userName"/>                  </token-split>              </arg-value>          </do-reformat-op-attr>      </actions>  </rule>