diff --git a/freqtrade/data/converter.py b/freqtrade/data/converter.py
index 4b4c89d08..049c399e4 100644
--- a/freqtrade/data/converter.py
+++ b/freqtrade/data/converter.py
@@ -122,7 +122,7 @@ def ohlcv_fill_up_missing_data(dataframe: DataFrame, timeframe: str, pair: str)
     return df
 
 
-def trim_dataframe(df: DataFrame, timerange, df_date_col: str = 'date',
+def trim_dataframe(df: DataFrame, timerange, *, df_date_col: str = 'date',
                    startup_candles: int = 0) -> DataFrame:
     """
     Trim dataframe based on given timerange
diff --git a/freqtrade/plot/plotting.py b/freqtrade/plot/plotting.py
index 7fd20f041..c45a09fbb 100644
--- a/freqtrade/plot/plotting.py
+++ b/freqtrade/plot/plotting.py
@@ -84,7 +84,7 @@ def init_plotscript(config, markets: List, startup_candles: int = 0):
     except ValueError as e:
         raise OperationalException(e) from e
     if not trades.empty:
-        trades = trim_dataframe(trades, timerange, 'open_date')
+        trades = trim_dataframe(trades, timerange, df_date_col='open_date')
 
     return {"ohlcv": data,
             "trades": trades,