docs: private static ExpressionPart getExpressionPart(String expressionPart,
                                                      ModelField currentFact) {
          if (currentFact == null) {
              return new ExpressionText(expressionPart);
          } else {
              return new ExpressionVariable(expressionPart,
                                            currentFact.getClassName(),
                                            currentFact.getType());
          }
      }