presto-ml/src/main/java/io/prestosql/plugin/ml/type/ClassifierParametricType.java/ClassifierParametricType/createType
class ClassifierParametricType:    @Override
    public Type createType(TypeManager typeManager, List<TypeParameter> parameters)
    {
        checkArgument(parameters.size() == 1, "Expected only one type, got %s", parameters);
        checkArgument(
                parameters.get(0).getKind() == ParameterKind.TYPE,
                "Expected type as a parameter, got %s",
                parameters);
        return new ClassifierType(parameters.get(0).getType());
    }