onGanttReady is not fired on 7.1.2

I am using the version 7.1.2 , and i have the ganttInstance using Gantt.getGanttInstance(), i want add the the task Layer, so one the solution provided is add the layers onGanttReady event. But event is not seems to be working

Hello Rakesh,
I couldn’t reproduce the issue in the following snippet:
http://snippet.dhtmlx.com/5/9ce145fd4

Probably, the issue is related to the Gantt configuration, but it is hard to suggest what might be wrong as I don’t see your code.
Please, add your configuration in the following snippet and make sure that the issue is reproduced there:
https://snippet.dhtmlx.com/38ee1b370
Then, click on the Share button and send me the link.
Or send me a ready demo with all the necessary Javascript and CSS files so that I can reproduce the issue locally.