rewrite retry

csst_common/utils/_retry.py

@@ -17,7 +17,7 @@ def retry(func, *args, **kwargs):
     else:
         n_try = 5
     # is DFS?
-    is_dfs = func.__self__.__class__.__module__.startswith("csst_dfs_client")
+    is_dfs = func.__class__.__module__.startswith("csst_dfs_client")
     # start trials
     for attempt in range(n_try):
         print(f"Trial #{attempt}: call {func}")