diff --git a/runtime/Python3/src/antlr4/atn/ATNDeserializer.py b/runtime/Python3/src/antlr4/atn/ATNDeserializer.py
index e0495dd570..d7b1768424 100644
--- a/runtime/Python3/src/antlr4/atn/ATNDeserializer.py
+++ b/runtime/Python3/src/antlr4/atn/ATNDeserializer.py
@@ -22,7 +22,7 @@ def __init__(self, options : ATNDeserializationOptions = None):
             options = ATNDeserializationOptions.defaultOptions
         self.deserializationOptions = options
 
-    def deserialize(self, data : int):
+    def deserialize(self, data : [int]):
         self.data = data
         self.pos = 0
         self.checkVersion()