Add the default (no-op) reranker for AAP

Author: TamiTakamiya

ols/customize/aap/reranker.py

@@ -0,0 +1,14 @@
+"""Reranker for post-processing the Vector DB search results."""
+
+import logging
+
+from llama_index.core.schema import NodeWithScore
+
+logger = logging.getLogger(__name__)
+
+
+def rerank(retrieved_nodes: list[NodeWithScore]) -> list[NodeWithScore]:
+    """Rerank Vector DB search results."""
+    message = f"reranker.rerank() is called with {len(retrieved_nodes)} result(s)."
+    logger.debug(message)
+    return retrieved_nodes