<xsd:simpleType name="Code_SSR">
    <xsd:annotation>
        <xsd:documentation source="Description">Special Service Request code containing 4 letters as defined by IATA</xsd:documentation>
        <xsd:appinfo>
            <otm:OTA2Entity type="Simple" xmlns:otm="http://www.OpenTravel.org/ns/OTA2/AppInfo_v01_00">Code_SSR</otm:OTA2Entity>
            <otm:Example context="Common" xmlns:otm="http://www.OpenTravel.org/ns/OTA2/AppInfo_v01_00">BIKE</otm:Example>
        </xsd:appinfo>
    </xsd:annotation>
    <xsd:restriction base="xsd:string">
        <xsd:pattern value="[A-Z]{4}" />
    </xsd:restriction>
</xsd:simpleType>