Initial UML model:

<model xmi:version="20131001" xmlns:xmi="http://www.omg.org/spec/XMI/20131001" xmlns:uml="http://www.eclipse.org/uml2/5.0.0/UML" xmi:id="_gajMIF7MEeSa4sJ83GIR5A" name="org.test">
	<packagedElement xmi:type="uml-Class" xmi:id="_gajMIV7MEeSa4sJ83GIR5A" name="LudeImpl">
		<ownedAttribute xmi:id="_gajMIl7MEeSa4sJ83GIR5A" name="myAttribute" visibility="private" type="_gajzMV7MEeSa4sJ83GIR5A"/>
		<ownedOperation xmi:id="_gajMI17MEeSa4sJ83GIR5A" name="getMyAttribute" visibility="public">
			<uml-ownedParameter xmi:id="_gajMJF7MEeSa4sJ83GIR5A" type="_gajzMV7MEeSa4sJ83GIR5A" direction="return"/>
		</ownedOperation>
	</packagedElement>
	<packagedElement xmi:type="uml-Package" xmi:id="_gajzMF7MEeSa4sJ83GIR5A" name="runtime.types" visibility="private">
		<packagedElement xmi:type="uml-Class" xmi:id="_gajzMV7MEeSa4sJ83GIR5A" name="java.lang.String" visibility="package"/>
	</packagedElement>
	<packagedElement xmi:type="uml-Class" xmi:id="_gajzMl7MEeSa4sJ83GIR5A" name="Interlude">
		<ownedOperation xmi:id="_gajzM17MEeSa4sJ83GIR5A" name="getMyAttribute" visibility="public">
			<uml-ownedParameter xmi:id="_gajzNF7MEeSa4sJ83GIR5A" type="_gajzMV7MEeSa4sJ83GIR5A" direction="return"/>
		</ownedOperation>
	</packagedElement>
	<packagedElement xmi:type="uml-Realization" xmi:id="_NP8jAF7NEeSa4sJ83GIR5A" client="_gajzMl7MEeSa4sJ83GIR5A _gajMIV7MEeSa4sJ83GIR5A"/>
</model>

Adapted UML model (for Polymer elements names compatibility):

<uml-model xmi:version="20131001" xmlns:xmi="http://www.omg.org/spec/XMI/20131001" xmlns:uml="http://www.eclipse.org/uml2/5.0.0/UML" xmi:id="_gajMIF7MEeSa4sJ83GIR5A" name="org.test">
	<uml-packagedElement type="uml-Class" xmi:id="_gajMIV7MEeSa4sJ83GIR5A" name="LudeImpl">
		<uml-ownedAttribute xmi:id="_gajMIl7MEeSa4sJ83GIR5A" name="myAttribute" visibility="private" type="_gajzMV7MEeSa4sJ83GIR5A"/>
		<uml-ownedOperation xmi:id="_gajMI17MEeSa4sJ83GIR5A" name="getMyAttribute" visibility="public">
			<uml-ownedParameter xmi:id="_gajMJF7MEeSa4sJ83GIR5A" type="_gajzMV7MEeSa4sJ83GIR5A" direction="return"/>
		</uml-ownedOperation>
	</uml-packagedElement>
	<uml-packagedElement type="uml-Package" xmi:id="_gajzMF7MEeSa4sJ83GIR5A" name="runtime.types" visibility="private">
		<uml-packagedElement type="uml-Class" xmi:id="_gajzMV7MEeSa4sJ83GIR5A" name="java.lang.String" visibility="package"/>
	</uml-packagedElement>
	<uml-packagedElement type="uml-Class" xmi:id="_gajzMl7MEeSa4sJ83GIR5A" name="Interlude">
		<uml-ownedOperation xmi:id="_gajzM17MEeSa4sJ83GIR5A" name="getMyAttribute" visibility="public">
			<uml-ownedParameter xmi:id="_gajzNF7MEeSa4sJ83GIR5A" type="_gajzMV7MEeSa4sJ83GIR5A" direction="return"/>
		</uml-ownedOperation>
	</uml-packagedElement>
	<uml-packagedElement type="uml-Realization" xmi:id="_NP8jAF7NEeSa4sJ83GIR5A" client="_gajzMl7MEeSa4sJ83GIR5A _gajMIV7MEeSa4sJ83GIR5A"/>
</uml-model>

Result: