Addressing Ruben's feedback

Author: leandrodamascena

aws_lambda_powertools/logging/logger.py

@@ -584,7 +584,7 @@ def append_keys(self, **additional_keys: object) -> None:
         self.registered_formatter.append_keys(**additional_keys)
 
     def get_current_keys(self) -> Dict[str, Any]:
-        if hasattr(self.registered_formatter, "log_format"):
+        if isinstance(self.registered_formatter, LambdaPowertoolsFormatter):
             return self.registered_formatter.get_current_keys()
 
         return {}

docs/core/logger.md

@@ -742,7 +742,7 @@ The `log` argument is the final log record containing [our standard keys](#stand
 For exceptional cases where you want to completely replace our formatter logic, you can subclass `BasePowertoolsFormatter`.
 
 ???+ warning
-    You will need to implement `append_keys`, `clear_state`, override `format`, and optionally `get_current_keys`, and `remove_keys` to keep the same feature set Powertools for AWS Lambda (Python) Logger provides. This also means keeping state of logging keys added.
+    You will need to implement `append_keys`, `clear_state`, override `format`, and optionally `get_current_keys`, and `remove_keys` to keep the same feature set Powertools for AWS Lambda (Python) Logger provides. This also means tracking the added logging keys.
 
 === "bring_your_own_formatter_from_scratch.py"