refactor(module): simplify service instantiation with generics

app/helper/downloader.py

@@ -1,23 +1,5 @@
-from typing import List
-
-from app.db.systemconfig_oper import SystemConfigOper
-from app.schemas.system import DownloaderConf
-from app.schemas.types import SystemConfigKey
-
-
 class DownloaderHelper:
     """
     下载器帮助类
     """
-
-    def __init__(self):
-        self.systemconfig = SystemConfigOper()
-
-    def get_downloaders(self) -> List[DownloaderConf]:
-        """
-        获取下载器
-        """
-        downloader_confs: List[dict] = self.systemconfig.get(SystemConfigKey.Downloaders)
-        if not downloader_confs:
-            return []
-        return [DownloaderConf(**conf) for conf in downloader_confs]
+    pass