fix: ensure type on method parameter

(cherry picked from commit c055e86e51)

erpnext/accounts/doctype/payment_request/payment_request.py

@@ -545,6 +545,9 @@ def make_payment_request(**args):
 	if args.dt not in ALLOWED_DOCTYPES_FOR_PAYMENT_REQUEST:
 		frappe.throw(_("Payment Requests cannot be created against: {0}").format(frappe.bold(args.dt)))
 
+	if args.dn and not isinstance(args.dn, str):
+		frappe.throw(_("Invalid parameter. 'dn' should be of type str"))
+
 	ref_doc = args.ref_doc or frappe.get_doc(args.dt, args.dn)
 	if not args.get("company"):
 		args.company = ref_doc.company