LiteralValueUse.value is not optional.

TestDescriptionLanguage/tdl.uml

@@ -621,8 +621,6 @@
             <generalization xmi:type="uml:Generalization" xmi:id="_ySa5gUN-Eeq6JfofCdGheg" general="_WJp7wGjrEeSGaIFXgYnwew"/>
             <ownedAttribute xmi:type="uml:Property" xmi:id="_kmdqYEN_Eeq6JfofCdGheg" name="value" visibility="public" isUnique="false">
               <type xmi:type="uml:PrimitiveType" href="pathmap://UML_LIBRARIES/UMLPrimitiveTypes.library.uml#String"/>
-              <lowerValue xmi:type="uml:LiteralInteger" xmi:id="_kmdqYUN_Eeq6JfofCdGheg"/>
-              <upperValue xmi:type="uml:LiteralUnlimitedNatural" xmi:id="_kmdqYkN_Eeq6JfofCdGheg" value="1"/>
             </ownedAttribute>
           </packagedElement>
         </packagedElement>