Custom script to total BOM qty (code seems right but few errors need help)!1

This is the script I’m trying for total qty but getting an error

//setting total qty

frappe.ui.form.on(‘BOM’, ‘validate’, 'function(frm) {
set_total_qty(frm);
})

frappe.ui.form.on(‘BOM Item’, ‘qty’, function(frm, cdt, cdn) {
set_total_qty(frm);
})

var set_total_qty = function(frm) {
var total_qty = 0.0;
$.each(frm.doc.items, functions(i, row) {
total_qty += flt(row.qty);
})
frm.set_value(‘total_qty’, total_qty);
frm.refresh();
}