Extract .last_result.json to constant

freqtrade/data/btanalysis.py

@@ -10,6 +10,7 @@ import pandas as pd
 from datetime import timezone
 
 from freqtrade import persistence
+from freqtrade.constants import LAST_BT_RESULT_FN
 from freqtrade.misc import json_load
 from freqtrade.persistence import Trade
 
@@ -34,7 +35,7 @@ def get_latest_backtest_filename(directory: Union[Path, str]) -> str:
         directory = Path(directory)
     if not directory.is_dir():
         raise ValueError(f"Directory '{directory}' does not exist.")
-    filename = directory / '.last_result.json'
+    filename = directory / LAST_BT_RESULT_FN
 
     if not filename.is_file():
         raise ValueError(f"Directory '{directory}' does not seem to contain backtest statistics yet.")
@@ -43,7 +44,7 @@ def get_latest_backtest_filename(directory: Union[Path, str]) -> str:
         data = json_load(file)
 
     if 'latest_backtest' not in data:
-        raise ValueError("Invalid '.last_result.json' format.")
+        raise ValueError(f"Invalid '{LAST_BT_RESULT_FN}' format.")
 
     return data['latest_backtest']