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Google script. Creat trigger automatically

I am new in js and it is my first script. The idea of my project is creat event in my google calander every time when I edit (write values) to some cell. The problem is that I can't use onEdit() function because I need permission (use calander from sheet level). So I creat installable trigger like this:

function createEditTrigger() {
var ss = SpreadsheetApp.getActive();
ScriptApp.newTrigger('ToCalendar')
.forSpreadsheet(ss)
.onEdit()
.create();
}


Everything is fine but now I want creat this trigger automatically to my sheet not manually like I have now.

My idea was to use function onOpen() like this:

function onOpen() {
createEditTrigger();
Logger.log("hi");
}


but it of course will creat many the same triggers.

Is there any way to creat trigger automatically only once?
I will be grateful for all answers!

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