Add an explanation on an obscure bit of the code.

lolafect/lolaconfig.py

@@ -24,6 +24,9 @@ def _needs_env_data(method: Callable) -> Callable:
     """
 
     def wrapper(self, *args, **kwargs):
+        # Many methods that use this decorator used to provide the option of passing in
+        # an s3_reader different than the default one. Here, we check if the kwargs
+        # contain one and, if so, use that instead of the default one.
         self.fetch_env_data(kwargs.get("s3_reader", None))
         return method(self, *args, **kwargs)