gml:NilReasonEnumeration

<simpleType name="NilReasonEnumeration">
  <union>
    <simpleType>
      <restriction base="string">
        <enumeration value="inapplicable"/>
        <enumeration value="missing"/>
        <enumeration value="template"/>
        <enumeration value="unknown"/>
        <enumeration value="withheld"/>
      </restriction>
    </simpleType>
    <simpleType>
      <restriction base="string">
        <pattern value="other:\w{2,}"/>
      </restriction>
    </simpleType>
  </union>
</simpleType>