From 85fedf95e85a871579731a55911694d406660bb4 Mon Sep 17 00:00:00 2001
From: hroff-1902 <hroff_raeyd9tzpttf@mail.ru>
Date: Tue, 2 Jun 2020 18:43:37 +0300
Subject: [PATCH] Make mypy happy

---
 freqtrade/exchange/exchange.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/freqtrade/exchange/exchange.py b/freqtrade/exchange/exchange.py
index 6275b0eda..397e0c1a7 100644
--- a/freqtrade/exchange/exchange.py
+++ b/freqtrade/exchange/exchange.py
@@ -890,7 +890,7 @@ class Exchange:
         logger.debug(f"_async_get_trade_history(), pair: {pair}, "
                      f"since: {since}, until: {until}, from_id: {from_id}")
 
-        if not until:
+        if until is None:
             exchange_msec = ccxt.Exchange.milliseconds()
             logger.debug(f"Exchange milliseconds: {exchange_msec}")
             until = exchange_msec