diff --git a/frappe/core/doctype/doctype/doctype.py b/frappe/core/doctype/doctype/doctype.py
index e0b9d15114..6eef5a4023 100644
--- a/frappe/core/doctype/doctype/doctype.py
+++ b/frappe/core/doctype/doctype/doctype.py
@@ -123,7 +123,7 @@ class DocType(Document):
 		}
 
 		for docfield in self.get("fields") or []:
-			conflict_type = ""
+			conflict_type = None
 			field = docfield.fieldname
 			field_label = docfield.label or docfield.fieldname