diff --git a/freqtrade/data/converter/orderflow.py b/freqtrade/data/converter/orderflow.py
index ca19a2622..f0cc726d2 100644
--- a/freqtrade/data/converter/orderflow.py
+++ b/freqtrade/data/converter/orderflow.py
@@ -12,7 +12,7 @@ from typing import Tuple
 import numpy as np
 import pandas as pd
 
-from freqtrade.constants import DEFAULT_ORDERFLOW_COLUMNS
+from freqtrade.constants import DEFAULT_ORDERFLOW_COLUMNS, Config
 from freqtrade.enums import RunMode
 from freqtrade.exceptions import DependencyException
 
@@ -63,7 +63,7 @@ def _calculate_ohlcv_candle_start_and_end(df: pd.DataFrame, timeframe: str):
 
 def populate_dataframe_with_trades(
     cached_grouped_trades: OrderedDict[Tuple[datetime, datetime], pd.DataFrame],
-    config,
+    config: Config,
     dataframe: pd.DataFrame,
     trades: pd.DataFrame,
 ) -> Tuple[pd.DataFrame, OrderedDict[Tuple[datetime, datetime], pd.DataFrame]]: