code: public static ModelDiff createModelDiff(OpenEngSBModel before, OpenEngSBModel after) {
          ModelDiff diff = new ModelDiff(before, after);
          calculateDifferences(diff);
          return diff;
      }
docs: Creates an instance of the ModelDiff class based on the both models which are passed to the function. It
  instantiate the class and calculates the differences of this two models.