code: @XmlElementDecl(namespace = "http://www.w3.org/1998/Math/MathML", name = "mtr")
      public JAXBElement<MtrType> createMtr(MtrType value) {
          return new JAXBElement<MtrType>(_Mtr_QNAME, MtrType.class, null, value);
      }
docs: Create an instance of {@link JAXBElement }{@code <}{@link MtrType }{@code >}}