diff --git a/erpnext/patches/v11_0/refactor_naming_series.py b/erpnext/patches/v11_0/refactor_naming_series.py
index 9faf4cd..3a2cdbd 100644
--- a/erpnext/patches/v11_0/refactor_naming_series.py
+++ b/erpnext/patches/v11_0/refactor_naming_series.py
@@ -93,13 +93,13 @@
 			continue
 		if not frappe.db.has_column(doctype, 'naming_series'):
 			continue
-		series_to_preserve = filter(None, get_series_to_preserve(doctype))
+		series_to_preserve = list(filter(None, get_series_to_preserve(doctype)))
 		default_series = get_default_series(doctype)
 
 		if not series_to_preserve:
 			continue
 		existing_series = (frappe.get_meta(doctype).get_field("naming_series").options or "").split("\n")
-		existing_series = filter(None, [d.strip() for d in existing_series])
+		existing_series = list(filter(None, [d.strip() for d in existing_series]))
 
 		# set naming series property setter
 		series_to_preserve = list(set(series_to_preserve + existing_series))