<xs:attribute name="IssuanceMethod" use="optional">
    <xs:annotation>
        <xs:documentation xml:lang="en">Specifies method of bagtag issuance.</xs:documentation>
    </xs:annotation>
    <xs:simpleType>
        <xs:restriction base="xs:NMTOKEN">
            <xs:enumeration value="Agent">
                <xs:annotation>
                    <xs:documentation xml:lang="en">Agent is issuing a bag tag.</xs:documentation>
                </xs:annotation>
            </xs:enumeration>
            <xs:enumeration value="Skycap">
                <xs:annotation>
                    <xs:documentation xml:lang="en">Skycap (or porter) is issuing a bag tag.</xs:documentation>
                </xs:annotation>
            </xs:enumeration>
            <xs:enumeration value="SelfService">
                <xs:annotation>
                    <xs:documentation xml:lang="en">A passenger is using a self service unit (SSU) or self service device (SSD) to issue bag tags.</xs:documentation>
                </xs:annotation>
            </xs:enumeration>
            <xs:enumeration value="Vendor">
                <xs:annotation>
                    <xs:documentation xml:lang="en">A third party contractor is providing service to issue bag tags.</xs:documentation>
                </xs:annotation>
            </xs:enumeration>
        </xs:restriction>
    </xs:simpleType>
</xs:attribute>