diff --git a/mypy/nodes.py b/mypy/nodes.py
index fe41777c55f7f..6c23c51dfcd39 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -1155,7 +1155,7 @@ def serialize(self) -> JsonDict:
         }
 
     @classmethod
-    def deserialize(self, data: JsonDict) -> ClassDef:
+    def deserialize(cls, data: JsonDict) -> ClassDef:
         assert data[".class"] == "ClassDef"
         res = ClassDef(
             data["name"],