1<?xml version="1.0"?>
2<grammar xmlns="http://relaxng.org/ns/structure/1.0">
3  <start>
4    <element name="test" ns="http://example.com/1/">
5      <zeroOrMore>
6        <attribute>
7          <choice>
8            <nsName ns="http://example.com/1/"/>
9            <nsName ns="http://example.com/2/"/>
10          </choice>
11          <text/>
12        </attribute>
13      </zeroOrMore>
14    </element>
15  </start>
16</grammar>
17