[None][autodeploy] fix weight extraction for graph based quantized checkpoints (#9109)

Signed-off-by: Fridah-nv <[email protected]>

Author: Fridah-nv

tensorrt_llm/_torch/auto_deploy/utils/node_utils.py

@@ -139,14 +139,15 @@ def find_get_attr_node(weight_node: Node) -> Node:
             n for n in node.args if isinstance(n, Node) and find_get_attr_node(n) is not None
         ]
         # can be two weights (if bias weight is present)
-        assert len(weight_nodes) >= 1, (
+        weight_node = None
+        if weight_nodes:
+            weight_node = weight_nodes[0]
+        # for modelopt quantized graph, there will be a quantize_op
+        _, weight_params, _ = get_quantization_params_from_linear_node(node)
+        weight_node = weight_params.input_node if weight_params else weight_node
+        assert weight_node is not None, (
             "Expected exactly at least one weight node in the parametrized node"
         )
-        weight_node = weight_nodes[0]
-    # for modelopt quantized graph, there will be a quantize_op
-    _, weight_params, _ = get_quantization_params_from_linear_node(node)
-    weight_node = weight_params.input_node if weight_params else weight_node
-
     return find_get_attr_node(weight_node)