<xs:attribute name="RangePosition" use="optional">
    <xs:annotation>
        <xs:documentation xml:lang="en">Specifies whether the first or last flight segment reference number in a range.</xs:documentation>
    </xs:annotation>
    <xs:simpleType>
        <xs:restriction base="xs:NMTOKEN">
            <xs:enumeration value="First">
                <xs:annotation>
                    <xs:documentation xml:lang="en">Indicates that the flight reference number represents the first flight in a range of flights to be ticketed. </xs:documentation>
                </xs:annotation>
            </xs:enumeration>
            <xs:enumeration value="Last">
                <xs:annotation>
                    <xs:documentation xml:lang="en">Indicates that the flight reference number represents the last flight in a range of flights to be ticketed. </xs:documentation>
                </xs:annotation>
            </xs:enumeration>
        </xs:restriction>
    </xs:simpleType>
</xs:attribute>