fix loop variable names

Author: blink1073

traitlets/config/application.py

@@ -830,7 +830,7 @@ def _load_config_files(cls, basefilename, path=None, log=None, raise_config_file
 
         if not isinstance(path, list):
             path = [path]
-        for path in path[::-1]:
+        for path in reversed(path):
             # path list is in descending priority order, so load files backwards:
             pyloader = cls.python_config_loader_class(basefilename + ".py", path=path, log=log)
             if log:
@@ -882,17 +882,17 @@ def load_config_file(self, filename, path=None):
         """Load config files by filename and path."""
         filename, ext = os.path.splitext(filename)
         new_config = Config()
-        for (config, filename) in self._load_config_files(
+        for (config, fname) in self._load_config_files(
             filename,
             path=path,
             log=self.log,
             raise_config_file_errors=self.raise_config_file_errors,
         ):
             new_config.merge(config)
             if (
-                filename not in self._loaded_config_files
+                fname not in self._loaded_config_files
             ):  # only add to list of loaded files if not previously loaded
-                self._loaded_config_files.append(filename)
+                self._loaded_config_files.append(fname)
         # add self.cli_config to preserve CLI config priority
         new_config.merge(self.cli_config)
         self.update_config(new_config)