Converting Unix timestamp in Google App scripts

I am new to Google App Script and am currently working on a project to help myself get familiar with it. My project has a part where I have to convert Unix Timestamp objects in nested JSON to human-readable time. As I don't know about converting timestamps in Google App scripts, I looked into the documentation and found "Utilities.formatDate()".

I tried using it on an example timestamp to see how it works and if it can be used for my needs. So I took a timestamp from the data and tried converting it with this code.

 function blah () {
  var tim = "1572401067";
  var formattedDate = Utilities.formatDate(tim, "GMT+5:30", "MM-dd-yyyy HH:mm:ss");

  Logger.log(formattedDate);
  }

It ends with an error saying:

Cannot find method formatDate(string,string,string). (line 3, file "Code")Dismiss

What am I doing wrong here?

Copyright Notice：Content Author:「user12297498」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/58626103/converting-unix-timestamp-in-google-app-scripts