diff --git a/freqtrade/freqtradebot.py b/freqtrade/freqtradebot.py
index e8149794e..cf9b6e17b 100644
--- a/freqtrade/freqtradebot.py
+++ b/freqtrade/freqtradebot.py
@@ -278,7 +278,7 @@ class FreqtradeBot(LoggingMixin):
             }
             self.rpc.send_msg(msg)
 
-    def _refresh_active_whitelist(self, trades: List[Trade] = []) -> List[str]:
+    def _refresh_active_whitelist(self, trades: Optional[List[Trade]] = None) -> List[str]:
         """
         Refresh active whitelist from pairlist or edge and extend it with
         pairs that have open trades.