export xml in struct example (jsut for easier testing debug)

examples/server-data-type-definition.py

@@ -18,16 +18,16 @@ async def main():
     uri = 'http://examples.freeopcua.github.io'
     idx = await server.register_namespace(uri)
 
-    await new_struct(server, idx, "MyStruct", [
+    snode1, _ = await new_struct(server, idx, "MyStruct", [
         new_struct_field("MyBool", ua.VariantType.Boolean),
         new_struct_field("MyUInt32List", ua.VariantType.UInt32, array=True),
     ])
-    await new_struct(server, idx, "MyOptionalStruct", [
+    snode2, _ = await new_struct(server, idx, "MyOptionalStruct", [
         new_struct_field("MyBool", ua.VariantType.Boolean),
         new_struct_field("MyUInt32List", ua.VariantType.UInt32, array=True),
         new_struct_field("MyInt64", ua.VariantType.Int64, optional=True),
     ])
-    await new_enum(server, idx, "MyEnum", [
+    enode = await new_enum(server, idx, "MyEnum", [
         "titi",
         "toto",
         "tutu",
@@ -35,13 +35,15 @@ async def main():
 
     await server.load_data_type_definitions()
 
-    await server.nodes.objects.add_variable(idx, "my_enum", ua.MyEnum.toto)
+    valnode = await server.nodes.objects.add_variable(idx, "my_enum", ua.MyEnum.toto)
     await server.nodes.objects.add_variable(idx, "my_struct", ua.Variant(ua.MyStruct(), ua.VariantType.ExtensionObject))
     my_struct_optional = ua.MyOptionalStruct()
     my_struct_optional.MyUInt32List = [45, 67]
     my_struct_optional.MyInt64 = -67
     await server.nodes.objects.add_variable(idx, "my_struct_optional", ua.Variant(my_struct_optional, ua.VariantType.ExtensionObject))
 
+    await server.export_xml([server.nodes.objects, server.nodes.root, snode1, snode2, enode, valnode], "structs_and_enum.xml")
+
     async with server:
         while True:
             await asyncio.sleep(1)