diff --git a/docs/examples/retrievers/ensemble_retrieval.ipynb b/docs/examples/retrievers/ensemble_retrieval.ipynb
index 073d6d3b53d0a..c1e1c238260cd 100644
--- a/docs/examples/retrievers/ensemble_retrieval.ipynb
+++ b/docs/examples/retrievers/ensemble_retrieval.ipynb
@@ -102,7 +102,9 @@
    "source": [
     "# try loading great gatsby\n",
     "\n",
-    "documents = SimpleDirectoryReader(input_files=[\"../../../examples/gatsby/gatsby_full.txt\"]).load_data()"
+    "documents = SimpleDirectoryReader(\n",
+    "    input_files=[\"../../../examples/gatsby/gatsby_full.txt\"]\n",
+    ").load_data()"
    ]
   },
   {
@@ -133,23 +135,23 @@
     "vector_indices = []\n",
     "query_engines = []\n",
     "for chunk_size in chunk_sizes:\n",
-    "    print(f'Chunk Size: {chunk_size}')\n",
+    "    print(f\"Chunk Size: {chunk_size}\")\n",
     "    service_context = ServiceContext.from_defaults(chunk_size=chunk_size, llm=llm)\n",
     "    service_contexts.append(service_context)\n",
     "    nodes = service_context.node_parser.get_nodes_from_documents(documents)\n",
-    "    \n",
+    "\n",
     "    # add chunk size to nodes to track later\n",
     "    for node in nodes:\n",
     "        node.metadata[\"chunk_size\"] = chunk_size\n",
     "        node.excluded_embed_metadata_keys = [\"chunk_size\"]\n",
     "        node.excluded_llm_metadata_keys = [\"chunk_size\"]\n",
-    "    \n",
+    "\n",
     "    nodes_list.append(nodes)\n",
-    "    \n",
+    "\n",
     "    # build vector index\n",
     "    vector_index = VectorStoreIndex(nodes)\n",
     "    vector_indices.append(vector_index)\n",
-    "    \n",
+    "\n",
     "    # query engines\n",
     "    query_engines.append(vector_index.as_query_engine())"
    ]
@@ -173,7 +175,7 @@
     "        retriever=vector_index.as_retriever(),\n",
     "        description=f\"Retrieves relevant context from the Great Gatsby (chunk size {chunk_size})\",\n",
     "    )\n",
-    "    retriever_tools.append(retriever_tool)\n"
+    "    retriever_tools.append(retriever_tool)"
    ]
   },
   {
@@ -185,15 +187,13 @@
    },
    "outputs": [],
    "source": [
-    "from llama_index.selectors.pydantic_selectors import (\n",
-    "    PydanticMultiSelector\n",
-    ")\n",
+    "from llama_index.selectors.pydantic_selectors import PydanticMultiSelector\n",
     "from llama_index.retrievers import RouterRetriever\n",
     "\n",
     "\n",
     "retriever = RouterRetriever(\n",
     "    selector=PydanticMultiSelector.from_defaults(llm=llm, max_outputs=4),\n",
-    "    retriever_tools=retriever_tools\n",
+    "    retriever_tools=retriever_tools,\n",
     ")"
    ]
   },
@@ -221,7 +221,9 @@
     }
    ],
    "source": [
-    "nodes = await retriever.aretrieve(\"Describe and summarize the interactions between Gatsby and Daisy\")"
+    "nodes = await retriever.aretrieve(\n",
+    "    \"Describe and summarize the interactions between Gatsby and Daisy\"\n",
+    ")"
    ]
   },
   {
@@ -560,7 +562,12 @@
    "outputs": [],
    "source": [
     "# define reranker\n",
-    "from llama_index.indices.postprocessor import LLMRerank, SentenceTransformerRerank, CohereRerank\n",
+    "from llama_index.indices.postprocessor import (\n",
+    "    LLMRerank,\n",
+    "    SentenceTransformerRerank,\n",
+    "    CohereRerank,\n",
+    ")\n",
+    "\n",
     "# reranker = LLMRerank()\n",
     "# reranker = SentenceTransformerRerank(top_n=10)\n",
     "reranker = CohereRerank(top_n=10)"
@@ -578,10 +585,7 @@
     "# define RetrieverQueryEngine\n",
     "from llama_index.query_engine import RetrieverQueryEngine\n",
     "\n",
-    "query_engine = RetrieverQueryEngine(\n",
-    "    retriever,\n",
-    "    node_postprocessors=[reranker]\n",
-    ")"
+    "query_engine = RetrieverQueryEngine(retriever, node_postprocessors=[reranker])"
    ]
   },
   {
@@ -604,7 +608,9 @@
     }
    ],
    "source": [
-    "response = query_engine.query(\"Describe and summarize the interactions between Gatsby and Daisy\")"
+    "response = query_engine.query(\n",
+    "    \"Describe and summarize the interactions between Gatsby and Daisy\"\n",
+    ")"
    ]
   },
   {
@@ -1003,7 +1009,9 @@
     }
    ],
    "source": [
-    "display_response(response, show_source=True, source_length=500, show_source_metadata=True)"
+    "display_response(\n",
+    "    response, show_source=True, source_length=500, show_source_metadata=True\n",
+    ")"
    ]
   },
   {
@@ -1019,6 +1027,7 @@
     "from collections import defaultdict\n",
     "import pandas as pd\n",
     "\n",
+    "\n",
     "def mrr_all(metadata_values, metadata_key, source_nodes):\n",
     "    # source nodes is a ranked list\n",
     "    # go through each value, find out positioning in source_nodes\n",
@@ -1027,18 +1036,17 @@
     "        mrr = 0\n",
     "        for idx, source_node in enumerate(source_nodes):\n",
     "            if source_node.node.metadata[metadata_key] == metadata_value:\n",
-    "                mrr = 1 / (idx+1)\n",
+    "                mrr = 1 / (idx + 1)\n",
     "                break\n",
     "            else:\n",
     "                continue\n",
-    "                \n",
+    "\n",
     "        # normalize AP, set in dict\n",
     "        value_to_mrr_dict[metadata_value] = mrr\n",
-    "        \n",
+    "\n",
     "    df = pd.DataFrame(value_to_mrr_dict, index=[\"MRR\"])\n",
     "    df.style.set_caption(\"Mean Reciprocal Rank\")\n",
-    "    return df\n",
-    "        "
+    "    return df"
    ]
   },
   {
@@ -1108,7 +1116,7 @@
    "source": [
     "# Compute the Mean Reciprocal Rank for each chunk size (higher is better)\n",
     "# we can see that chunk size of 256 has the highest ranked results.\n",
-    "print('Mean Reciprocal Rank for each Chunk Size')\n",
+    "print(\"Mean Reciprocal Rank for each Chunk Size\")\n",
     "mrr_all(chunk_sizes, \"chunk_size\", response.source_nodes)"
    ]
   },
@@ -1143,7 +1151,9 @@
    },
    "outputs": [],
    "source": [
-    "response_1024 = query_engine_1024.query(\"Describe and summarize the interactions between Gatsby and Daisy\")"
+    "response_1024 = query_engine_1024.query(\n",
+    "    \"Describe and summarize the interactions between Gatsby and Daisy\"\n",
+    ")"
    ]
   },
   {