diff --git a/rdagent/components/knowledge_management/graph.py b/rdagent/components/knowledge_management/graph.py
index 7b575e49c..4c448279f 100644
--- a/rdagent/components/knowledge_management/graph.py
+++ b/rdagent/components/knowledge_management/graph.py
@@ -136,10 +136,10 @@ def add_node(
         -------
 
         """
-        if self.get_node(node.id):
-            node = self.get_node(node.id)
-        elif self.find_node(content=node.content, label=node.label):
-            node = self.find_node(content=node.content, label=node.label)
+        if tmp_node := self.get_node(node.id):
+            node = tmp_node
+        elif tmp_node := self.find_node(content=node.content, label=node.label):
+            node = tmp_node
         else:
             # same_node = self.semantic_search(node=node.content, similarity_threshold=same_node_threshold, topk_k=1)
             # if len(same_node):
@@ -150,10 +150,10 @@ def add_node(
             self.nodes.update({node.id: node})
 
         if neighbor is not None:
-            if self.get_node(neighbor.id):
-                neighbor = self.get_node(neighbor.id)
-            elif self.find_node(content=neighbor.content, label=node.label):
-                neighbor = self.find_node(content=neighbor.content, label=node.label)
+            if tmp_neighbor := self.get_node(neighbor.id):
+                neighbor = tmp_neighbor
+            elif tmp_neighbor := self.find_node(content=neighbor.content, label=node.label):
+                neighbor = tmp_neighbor
             else:
                 # same_node = self.semantic_search(node=neighbor.content,
                 #                                  similarity_threshold=same_node_threshold, topk_k=1)