private methods is explicitly prefixed with _

package.json

@@ -1,6 +1,6 @@
 {
   "name": "animation-timeline-js",
-  "version": "2.0.3",
+  "version": "2.0.4",
   "description": "animation timeline control based on the canvas.",
   "main": "lib/animation-timeline.min.js",
   "types": "src/index.ts",