diff --git a/frappe/core/doctype/doctype/doctype.py b/frappe/core/doctype/doctype/doctype.py
index 1fa9f75156..3efbab2470 100644
--- a/frappe/core/doctype/doctype/doctype.py
+++ b/frappe/core/doctype/doctype/doctype.py
@@ -186,7 +186,7 @@ class DocType(Document):
 				for option in field.options.split("\n"):
 					new_options += option.strip()
 					new_options += "\n"
-				new_options.rstrip("\n")
+				new_options = new_options.rstrip("\n")
 				field.options = new_options
 
 	def validate_series(self, autoname=None, name=None):