<?xml version="1.0" ?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:complexType name="dog">
    <xs:attribute name="animal" type="yesno" fixed="yes" />
  </xs:complexType>

  <xs:simpleType name="yesno">
    <xs:restriction base="xs:string">
      <xs:enumeration value="yes" />
      <xs:enumeration value="no" />
    </xs:restriction>
  </xs:simpleType>
</xs:schema>