Improve playlist file opening check

src/importer/sources/retroarch_source.py

@@ -27,8 +27,7 @@ from time import time
 from src import shared
 from src.game import Game
 from src.importer.sources.location import Location
-from src.importer.sources.source import (Source, SourceIterationResult,
-                                         SourceIterator)
+from src.importer.sources.source import Source, SourceIterationResult, SourceIterator
 
 
 class RetroarchSourceIterator(SourceIterator):
@@ -40,12 +39,12 @@ class RetroarchSourceIterator(SourceIterator):
             if file.endswith(".lpl"):
                 playlist_files.append(file)
 
-        playlist_items = []
         for playlist_file in playlist_files:
-            open_file = open(
-                str(self.source.config_location["playlists"]) + "/" + playlist_file
-            )
             try:
+                with open(
+                    self.source.config_location["playlists"] / playlist_file,
+                    encoding="utf-8",
+                ) as open_file:
                     playlist_json = json.load(open_file)
             except (JSONDecodeError, OSError, KeyError):
                 logging.warning("Cannot read playlist file: %s", str(playlist_file))