unknown command ua_generate_nodeset_and_datatypes

Following the official CMake documentation, this is not how one defines a macro. How can this work for you?
I'm getting the error message

```
CMake Error at CMakeLists.txt:13 (ua_generate_nodeset_and_datatypes):
  Unknown CMake command "ua_generate_nodeset_and_datatypes".
```

See
https://cmake.org/cmake/help/v3.20/command/macro.html