How to change image sequence frame rate ?

Hello!

I write script which import image sequences to the project. Everything works ok.

Now I need to change frame rate for that image sequences using extra info.

I tried this way:

var proj = app.project;

        var importOpts = new ImportOptions( new File("/d/Scripts/df_2_aefx/test_001.dgn/test_001_Take_01/test_001_01_X1/test_001_01_X1_00 01.jpg"));

            importOpts.sequence= 1;

            var importImg = proj.importFile (importOpts);

            Window.alert(importImg);

            importImg.confromFrameRate=30.0;

But it doesn't work, the fps of layer stays that one is set in Preferences->Import->Sequnce Footage

How should I change frame rate for imported image sequence? (or interpet footage ?)