Update Items Button at Quotation

Hy, through client script I have created Update Items Button at quotation to update item code, rate etc. after submitting Quotation, like that at Sales Order.

frappe.ui.form.on('Quotation', {
    refresh: function(frm) {
        // Show "Update Items" button only if the document is submitted (docstatus == 1)
        if (frm.doc.docstatus == 1) {
            // Add "Update Items" button
            frm.add_custom_button(__('Update Items'), function() {
                // Fetch the existing items from the quotation's item table
                frappe.call({
                    method: 'frappe.client.get',
                    args: {
                        doctype: 'Quotation',
                        name: frm.doc.name
                    },
                    callback: function(r) {
                        if (r.message) {
                            // Clear existing items in the grid to avoid duplicates
                            frm.clear_table('items');

                            // Loop through each item in the quotation and add it to the item grid for editing
                            r.message.items.forEach(function(item) {
                                let child = frm.add_child('items');
                                child.item_code = item.item_code;
                                child.item_name = item.item_name;
                                child.qty = item.qty;
                                child.rate = item.rate;
                                child.amount = item.amount;
                                child.description = item.description;
                                child.uom = item.uom;
                                child.conversion_factor = item.conversion_factor;
                                // Add any additional fields you need to include
                            });

                            // Refresh the form and notify the user
                            frm.refresh_field('items');
                            frappe.msgprint(__('Items have been fetched. You can now update them.'));
                        }
                    }
                });

                // Enable save after fetching the items
                frm.enable_save();
            });
        }
    }
});

However button does not fetch items. Kindly help to modify code for fetching items to update at quotation. Thanks

Greetings! Experts

Kindly update code to fetch items at quotation for updating rate, qty, item like that of SO.

Thanks