diff --git a/erpnext/accounts/doctype/payment_request/payment_request.py b/erpnext/accounts/doctype/payment_request/payment_request.py
index c09391a8d41..1ba9cf1675d 100644
--- a/erpnext/accounts/doctype/payment_request/payment_request.py
+++ b/erpnext/accounts/doctype/payment_request/payment_request.py
@@ -1154,7 +1154,7 @@ def get_irequests_of_payment_request(doc: str | None = None) -> list:
 
 
 @frappe.whitelist()
-def get_available_payment_schedules(reference_doctype, reference_name):
+def get_available_payment_schedules(reference_doctype: str, reference_name: str):
 	ref_doc = frappe.get_doc(reference_doctype, reference_name)
 
 	if not hasattr(ref_doc, "payment_schedule") or not ref_doc.payment_schedule: