Gemini did alot of things

core/user.py

@@ -1,14 +1,18 @@
 class User:
-    def __init__(self, id, name) -> None:
+    def __init__(self, id, name, pin="4242") -> None:
         self.id = id
         self.name = name
         self.debt = 0.0
+        self.pin = pin
 
     def to_json(self):
-        return {"id": self.id, "name": self.name, "debt": self.debt}
+        return {"id": self.id, "name": self.name, "debt": self.debt, "pin": self.pin}
 
     @staticmethod
     def from_json(data):
-        user = User(data["id"], data["name"])
+        pin = data.get("pin")
+        if pin is None:
+            pin = "4242"
+        user = User(data["id"], data["name"], pin)
         user.debt = data["debt"]
         return user