Help me to make this script work, please!
function(){
app.findGrepPreferences.firstLineIndent = "8 mm";
app.findGrepPreferences.leftIndent = "8 mm";
app.changeGrepPreferences.firstLineIndent = "8 mm";
app.changeGrepPreferences.leftIndent = "16 mm";
app.selection[0].changeGrep();
app.findGrepPreferences.leftIndent = "16 mm";
app.changeGrepPreferences.leftIndent = "24 mm";
app.selection[0].changeGrep();
}