diff --git a/hummingbot/connector/exchange/bittrex/bittrex_order_book_tracker.py b/hummingbot/connector/exchange/bittrex/bittrex_order_book_tracker.py
index 4b779eba98..1a103368d3 100644
--- a/hummingbot/connector/exchange/bittrex/bittrex_order_book_tracker.py
+++ b/hummingbot/connector/exchange/bittrex/bittrex_order_book_tracker.py
@@ -184,7 +184,7 @@ async def _track_single_book(self, trading_pair: str):
                         d_bids, d_asks = active_order_tracker.convert_diff_message_to_order_book_row(diff_message)
                         order_book.apply_diffs(d_bids, d_asks, diff_message.update_id)
 
-                    self.logger().debug("Processed order book snapshot for %s.", trading_pair)
+                    self.logger().debug(f"Processed order book snapshot for {trading_pair}.")
             except asyncio.CancelledError:
                 raise
             except Exception: