old_contents: // Dpeendencies
  var EngineParserGen = require("../lib");
  
  // Initialize the parser-generator
  var epg = new EngineParserGen("test-app");
  
  // Rename layout->another_layout
  epg.renameInstance("layout", "another_layout", (err, toBeSaved, toBeDeleted) => {
      if (err) { return console.log(err); }
  
      // Save the changes on the disk
      epg.save({
  
          // delete these ones
          delete: toBeDeleted
          // delete: "layout"
          // delete: { layout: true, router: true }
  
          // Override these ones
        , save: toBeSaved
      }, function (err) {
          console.log(err || "Saved");
      });
  });
  
new_contents: // Dpendencies
  var EngineParserGen = require("../lib");
  
  // Initialize the parser-generator
  var epg = new EngineParserGen("test-app");
  
  // Rename layout->another_layout
  epg.renameInstance("layout", "another_layout", (err, toBeSaved, toBeDeleted) => {
      if (err) { return console.log(err); }
  
      // Save the changes on the disk
      epg.save({
  
          // Delete these ones
          delete: toBeDeleted
  
          // Override these ones
        , save: toBeSaved
      }, function (err) {
          console.log(err || "Saved");
      });
  });
  
subject: Clean up