List<Pair<String, ExpressionFunction>> readExpressions() {
            List<Pair<String, ExpressionFunction>> expressions = new ArrayList<>();
            ApplicationFile expressionPath = application.getFile(modelFiles.expressionsPath());
            if ( ! expressionPath.exists() || ! expressionPath.isDirectory()) return List.of();
            for (ApplicationFile expressionFile : expressionPath.listFiles()) {
                try (BufferedReader reader = new BufferedReader(expressionFile.createReader())) {
                    String name = expressionFile.getPath().getName();
                    expressions.add(new Pair<>(name, readExpression(name, reader)));
                }
                catch (IOException e) {
                    throw new UncheckedIOException("Failed reading " + expressionFile.getPath(), e);
                }
                catch (ParseException e) {
                    throw new IllegalStateException("Invalid stored expression in " + expressionFile, e);
                }
            }
            return expressions;
        }
Adds this expression to the application package, such that it can be read later.

@param name the name of this ranking expression - may have 1-3 parts separated by dot where the first part
            is always the model name
config-model/src/main/java/com/yahoo/vespa/model/ml/ConvertedModel.java