diff --git a/freqtrade/optimize/optimize_reports/bt_storage.py b/freqtrade/optimize/optimize_reports/bt_storage.py
index 21c87cfe7..47568cffd 100644
--- a/freqtrade/optimize/optimize_reports/bt_storage.py
+++ b/freqtrade/optimize/optimize_reports/bt_storage.py
@@ -11,7 +11,7 @@ from freqtrade.types import BacktestResultType
 logger = logging.getLogger(__name__)
 
 
-def generate_filename(recordfilename: Path, appendix: str, suffix: str) -> Path:
+def _generate_filename(recordfilename: Path, appendix: str, suffix: str) -> Path:
     """
     Generates a filename based on the provided parameters.
     :param recordfilename: Path object, which can either be a filename or a directory.
@@ -38,7 +38,7 @@ def store_backtest_stats(
     :param stats: Dataframe containing the backtesting statistics
     :param dtappendix: Datetime to use for the filename
     """
-    filename = generate_filename(recordfilename, dtappendix, '.json')
+    filename = _generate_filename(recordfilename, dtappendix, '.json')
 
     # Store metadata separately.
     file_dump_json(get_backtest_metadata_filename(filename), stats['metadata'])
@@ -69,7 +69,7 @@ def _store_backtest_analysis_data(
     :param dtappendix: Datetime to use for the filename
     :param name: Name to use for the file, e.g. signals, rejected
     """
-    filename = generate_filename(recordfilename, f"{dtappendix}_{name}", '.pkl')
+    filename = _generate_filename(recordfilename, f"{dtappendix}_{name}", '.pkl')
 
     file_dump_joblib(filename, data)