FileSystemStoragePathSource encountered a filesystem access error: Could not find base path

Having trouble with this simple tutorial:
“”

When I run this command:

# Start TensorFlow Serving container and open the REST API port
docker run -t --rm -p 8501:8501 \
    -v "$TESTDATA/saved_model_half_plus_two_cpu:/models/half_plus_two" \
    -e MODEL_NAME=half_plus_two \
    tensorflow/serving &```

I get this error:

> 2022-09-30 10:15:23.845663: E tensorflow_serving/sources/storage_path/file_system_storage_path_source.cc:353] FileSystemStoragePathSource encountered a filesystem access error: Could not find base path /models/half_plus_two for servable half_plus_two with error NOT_FOUND: /models/half_plus_two not found

Bear in mind, I know very little about docker. I am actually doing this simple tutorial to understand docker and how to use it to serve models