email-purpose

<xs:attribute name="email-purpose">
  <xs:simpleType>
    <xs:restriction base="xs:token">
      <xs:enumeration value="informal"/>
      <xs:enumeration value="general"/>
      <xs:enumeration value="advance"/>
      <xs:enumeration value="main"/>
    </xs:restriction>
  </xs:simpleType>
</xs:attribute>