code: @XmlElementDecl(namespace = "https://adwords.google.com/api/adwords/o/v201809", name = "RequestHeader")
      public JAXBElement<SoapHeader> createRequestHeader(SoapHeader value) {
          return new JAXBElement<SoapHeader>(_RequestHeader_QNAME, SoapHeader.class, null, value);
      }
docs: Create an instance of {@link JAXBElement }{@code <}{@link SoapHeader }{@code >}}