<xs:attribute name="usage">
<xs:annotation>
<xs:documentation>This attribute is used to express special usage of parent XML, such as Example</xs:documentation>
</xs:annotation>
<xs:simpleType>
<xs:restriction base="xs:NMTOKEN">
<xs:enumeration value="Definition"/>
<xs:enumeration value="Documentation">
<xs:annotation>
<xs:documentation xml:lang="en">This usage corresponds to a parent element that is only present for documentation purposes and should never be used as such in a real transaction. It would usually contain differnet items of the same type but suffisciently differnt to be detailed separately.</xs:documentation>
</xs:annotation>
</xs:enumeration>
<xs:enumeration value="Envelope"/>
<xs:enumeration value="Example">
<xs:annotation>
<xs:documentation xml:lang="EN">Used to mark an element as an example not to be used for the core documentation</xs:documentation>
</xs:annotation>
</xs:enumeration>
<xs:enumeration value="NotUsed">
<xs:annotation>
<xs:documentation xml:lang="EN">Used to mark an element as not to used at all up to now but present for future use. It should not be present in the core documentation</xs:documentation>
</xs:annotation>
</xs:enumeration>
<xs:enumeration value="Reference"/>
<xs:enumeration value="Standard"/>
<xs:enumeration value="Tip"/>
<xs:enumeration value="Usage"/>
<xs:enumeration value=< |