diff --git a/freqtrade/freqai/freqai_interface.py b/freqtrade/freqai/freqai_interface.py
index 03f458e47..a0f29a301 100644
--- a/freqtrade/freqai/freqai_interface.py
+++ b/freqtrade/freqai/freqai_interface.py
@@ -313,10 +313,9 @@ class IFreqaiModel(ABC):
                 dk.append_predictions(append_df)
             else:
                 if populate_indicators:
-                    timerange_str_from_main_df = (
-                        dataframe["date"].min().strftime("%Y%m%d") + "-" +
-                        dataframe["date"].max().strftime("%Y%m%d"))
-                    timerange = TimeRange.parse_timerange(timerange_str_from_main_df)
+                    tr_from_main_df = (f'{dataframe["date"].min().strftime("%Y%m%d")}'
+                                       f'-{dataframe["date"].max().strftime("%Y%m%d")}')
+                    timerange = TimeRange.parse_timerange(tr_from_main_df)
                     self.dd.load_all_pair_histories(timerange, self.dk)
                     corr_df, base_df = self.dd.get_base_and_corr_dataframes(timerange, pair, dk)
                     dataframe = self.dk.use_strategy_to_populate_indicators(