  <define name='svg.feUnsharpMask.content'>
    <zeroOrMore>
      <choice>
        <ref name='animate'/>
        <ref name='set'/>
      </choice>
    </zeroOrMore>
  </define>

  <define name='feUnsharpMask'>
    <element name='feUnsharpMask'>
      <ref name='attlist.feUnsharpMask'/>
      <ref name='svg.feUnsharpMask.content'/>
    </element>
  </define>

  <define name='attlist.feUnsharpMask' combine='interleave'>
    <ref name='svg.Core.attrib'/>
    <ref name='svg.FilterColor.attrib'/>
    <ref name='svg.FilterPrimitiveWithIn.attrib'/>
    <optional>
      <attribute name='amount'>
        <ref name='Number.datatype'/>
      </attribute>
      <attribute name='radius'>
        <ref name='NumberOptionalNumber.datatype'/>
      </attribute>
      <attribute name='threshold'>
        <ref name='Number.datatype'/>
      </attribute>
    </optional>
  </define>
  
