unknown module (symmetric_tilt_co_111) is used in the tutorial jupyternotebook for Co GB

In the tutorial jupyternotebook for Co GB, class `sample_STGB` is imported as:
```
from symmetric_tilt_co_111 import sample_STGB
```

However, there is no such kind of module. Is it just a mistake of a class in interface master.symmetric_tilt, i.e.:
```
from interfacemaster.symmetric_tilt import sample_STGB
```
or is it included in another script?