fix: validate_series
diff --git a/erpnext/setup/doctype/naming_series/naming_series.py b/erpnext/setup/doctype/naming_series/naming_series.py
index abff973..2ea0bc0 100644
--- a/erpnext/setup/doctype/naming_series/naming_series.py
+++ b/erpnext/setup/doctype/naming_series/naming_series.py
@@ -10,6 +10,7 @@
 from frappe.model.document import Document
 from frappe.model.naming import parse_naming_series
 from frappe.permissions import get_doctypes_with_read
+from frappe.core.doctype.doctype.doctype import validate_series
 
 class NamingSeriesNotSetError(frappe.ValidationError): pass
 
@@ -126,7 +127,7 @@
 		dt = frappe.get_doc("DocType", self.select_doc_for_series)
 		options = self.scrub_options_list(self.set_options.split("\n"))
 		for series in options:
-			dt.validate_series(series)
+			validate_series(dt, series)
 			for i in sr:
 				if i[0]:
 					existing_series = [d.split('.')[0] for d in i[0].split("\n")]