1  <element name="number" xmlns="http://relaxng.org/ns/structure/1.0">
 2     <attribute name="val">
 3        <list>
 4           <oneOrMore>
 5              <choice>
 6                 <value>1</value>
 7                 <value>2</value>
 8                 <value>3</value>
 9              </choice>
10           </oneOrMore>
11        </list>
12     </attribute>
13     <text/>
14  </element>