<xs:attribute name="SegmentType" use="required">
    <xs:annotation>
        <xs:documentation xml:lang="en">Used to specify what should be overridden.</xs:documentation>
    </xs:annotation>
    <xs:simpleType>
        <xs:restriction base="xs:NMTOKEN">
            <xs:enumeration value="Connection">
                <xs:annotation>
                    <xs:documentation xml:lang="en">Ignore that this is a connection segment.</xs:documentation>
                </xs:annotation>
            </xs:enumeration>
            <xs:enumeration value="Stopover">
                <xs:annotation>
                    <xs:documentation xml:lang="en">Ignore that this is a stopover segment.</xs:documentation>
                </xs:annotation>
            </xs:enumeration>
            <xs:enumeration value="TurnaroundPoint">
                <xs:annotation>
                    <xs:documentation xml:lang="en">Ignore that this is a turnaround point segment.</xs:documentation>
                </xs:annotation>
            </xs:enumeration>
        </xs:restriction>
    </xs:simpleType>
</xs:attribute>