Update aws_lambda_powertools/utilities/data_classes/cognito_user_pool_event.py

Co-authored-by: Leandro Damascena <[email protected]>
Signed-off-by: Stéphane MENG <[email protected]>

Author: knightmre

aws_lambda_powertools/utilities/data_classes/cognito_user_pool_event.py

@@ -1028,15 +1028,15 @@ def user_attributes(self) -> Dict[str, str]:
         return self["request"]["userAttributes"]
 
     @property
-    def client_metadata(self) -> Optional[Dict[str, str]]:
+    def client_metadata(self) -> Dict[str, str]:
         """One or more key-value pairs that you can provide as custom input to the
         custom email sender Lambda function trigger. To pass this data to your Lambda function,
         you can use the ClientMetadata parameter in the AdminRespondToAuthChallenge and
         RespondToAuthChallenge API actions. Amazon Cognito doesn't include data from the
         ClientMetadata parameter in AdminInitiateAuth and InitiateAuth API operations
         in the request that it passes to the post authentication function.
         """
-        return self["request"].get("clientMetadata")
+        return self["request"].get("clientMetadata") or {}
 
 
 class CustomEmailSenderTriggerEvent(BaseTriggerEvent):