diff --git a/Lib/fontTools/ttLib/tables/otBase.py b/Lib/fontTools/ttLib/tables/otBase.py
index 7689912a4..0ee5141a6 100644
--- a/Lib/fontTools/ttLib/tables/otBase.py
+++ b/Lib/fontTools/ttLib/tables/otBase.py
@@ -744,7 +744,7 @@ class ValueRecordFactory:
 	
 	"""Given a format code, this object convert ValueRecords."""
 
-	def __init__(self, valueFormat=0):
+	def __init__(self, valueFormat):
 		format = []
 		for mask, name, isDevice, signed in valueRecordFormat:
 			if valueFormat & mask: