diff --git a/lang_agent/base.py b/lang_agent/base.py
index 19b7897..68e7292 100644
--- a/lang_agent/base.py
+++ b/lang_agent/base.py
@@ -52,6 +52,6 @@ class ToolNodeBase(GraphBase):
     def get_delay_keys(self)->Tuple[str, str]:
         """
         returns 2 words, one for starting delayed yeilding, the other for ending delayed yielding,
-        they should be of format ('[key1]', '[key2]')
+        they should be of format ('[key1]', '[key2]'); key1 is starting, key2 is ending
         """
         return None, None
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