Update aws_lambda_powertools/utilities/data_classes/cognito_user_pool_event.py

Co-authored-by: Leandro Damascena <lcdama@amazon.pt>
Signed-off-by: Stéphane MENG <stephane.meng@gmail.com>

Author: knightmre

aws_lambda_powertools/utilities/data_classes/cognito_user_pool_event.py

@@ -576,8 +576,8 @@ def scopes_to_add(self, value: List[str]):
         self._data["scopesToAdd"] = value
 
     @property
-    def scopes_to_suppress(self) -> Optional[List[str]]:
-        return self.get("scopesToSuppress")
+    def scopes_to_suppress(self) -> List[str]:
+        return self.get("scopesToSuppress") or []
 
     @scopes_to_suppress.setter
     def scopes_to_suppress(self, value: List[str]):