toXML method
Implementation
String toXML() {
return '''
<device deviceIndex = "$deviceIndex" deviceName = "$deviceName" deviceParameterType = "$deviceParameterType" >
<supportedInterfaceModes>
${supportedInterfaceModes.map((e) => e.toXML()).join()}
</supportedInterfaceModes>
${deviceParameter.toXML()}
${devices.map((e) => e.toXML()).join()}
</device>
''';
}