fix: 修复 alist 存储

Author: tianxiu2b2t

core/storages/__init__.py

@@ -331,7 +331,7 @@ def empty():
                             logger.terror("storage.error.alist", status=result.code, message=result.message)
                         else:
                             self.cache.set(f"listfile_{root}", result, 30)
-                for r in result.data["content"] or []:
+                for r in ((result.data or []).get("content", None) or []):
                     file = File(
                         r["name"],
                         r["size"],