Lab 05 got IndexError: list index out of range when calling get_retrieved_nodes()

[SherryXDing]

For notebooks in 05_Semantic_Search_with_Reranking, when calling get_retrieved_nodes() with with_reranker=True, got IndexError: list index out of range.
Detailed error message:

IndexError Traceback (most recent call last)
Cell In[26], line 1
----> 1 retrieved_nodes1_withreranker = get_retrieved_nodes(
2 "How has AWS evolved?",
3 vector_top_k=1,
4 reranker_top_n=1,
5 with_reranker=True,
6 )

Cell In[22], line 30, in get_retrieved_nodes(query_str, vector_top_k, reranker_top_n, with_reranker)
21 if with_reranker:
22 # configure reranker
23 reranker = LLMRerank(
24 choice_batch_size=10, # 5,
25 top_n=reranker_top_n,
(...)
28
29 )
---> 30 retrieved_nodes = reranker.postprocess_nodes(retrieved_nodes, query_bundle)
32 return retrieved_nodes

File /opt/conda/lib/python3.10/site-packages/llama_index/indices/postprocessor/llm_rerank.py:85, in LLMRerank.postprocess_nodes(self, nodes, query_bundle)
78 # call each batch independently
79 raw_response = self.service_context.llm_predictor.predict(
80 self.choice_select_prompt,
81 context_str=fmt_batch_str,
82 query_str=query_str,
83 )
---> 85 raw_choices, relevances = self._parse_choice_select_answer_fn(
86 raw_response, len(nodes_batch)
87 )
88 choice_idxs = [int(choice) - 1 for choice in raw_choices]
89 choice_nodes = [nodes_batch[idx] for idx in choice_idxs]

File /opt/conda/lib/python3.10/site-packages/llama_index/indices/utils.py:104, in default_parse_choice_select_answer_fn(answer, num_choices, raise_error)
98 else:
99 raise ValueError(
100 f"Invalid answer line: {answer_line}. "
101 "Answer line must be of the form: "
102 "answer_num: , answer_relevance: "
103 )
--> 104 answer_num = int(line_tokens[0].split(":")[1].strip())
105 if answer_num > num_choices:
106 continue

IndexError: list index out of range