<xs:attribute name="win-type" use="optional">
    <xs:simpleType id="winType">
        <xs:restriction base="xs:string">
            <xs:enumeration id="winTypeForced" value="forced">
                <xs:annotation>
                    <xs:documentation>The point was made while the opponent for example
                                advanced towards the net.</xs:documentation>
                </xs:annotation>
            </xs:enumeration>
            <xs:enumeration id="winTypeUnforced" value="unforced">
                <xs:annotation>
                    <xs:documentation>The point was made regardless of specific actions by
                                the opponent.</xs:documentation>
                </xs:annotation>
            </xs:enumeration>
        </xs:restriction>
    </xs:simpleType>
</xs:attribute>