Refactor imports and add graph visualization section

Cleaned up unused imports and reorganized import statements for clarity. Added a new section for graph visualization, including error handling and user guidance for rendering issues. Updated code cell execution counts and improved markdown headings for better notebook structure.

Author: lfunderburk

ch8/yelp-navigator/langgraph_multiagent_supervisor.ipynb

@@ -62,7 +62,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 16,
+   "execution_count": 1,
    "id": "d530f52a",
    "metadata": {},
    "outputs": [
@@ -81,22 +81,18 @@
     "# =============================================================================\n",
     "\n",
     "import os\n",
-    "import json\n",
     "import requests\n",
-    "from typing import Annotated, TypedDict, List, Dict, Any\n",
-    "from operator import add\n",
+    "from typing import Dict, Any\n",
     "\n",
     "# LangGraph for building agent workflows\n",
     "from langgraph.graph import StateGraph, START, END, MessagesState\n",
-    "from langchain_core.messages import BaseMessage\n",
     "from langchain_openai import ChatOpenAI\n",
-    "from langchain_core.tools import tool\n",
-    "from langchain.agents import create_agent\n",
+    "\n",
     "from dotenv import load_dotenv\n",
     "from pathlib import Path\n",
-    "from langchain_ollama import ChatOllama\n",
-    "\n",
     "\n",
+    "# Optional if you don't want to use OpenAI\n",
+    "from langchain_ollama import ChatOllama\n",
     "\n",
     "# Load .env from the root of ch8 directory\n",
     "root_dir = Path(__file__).parent.parent if \"__file__\" in globals() else Path.cwd().parent\n",
@@ -133,7 +129,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 15,
+   "execution_count": 2,
    "id": "1e69191a",
    "metadata": {},
    "outputs": [
@@ -248,7 +244,7 @@
    "id": "e98ab8cc",
    "metadata": {},
    "source": [
-    "## Step 3: Initialize Language Model"
+    "## Initialize Language Model"
    ]
   },
   {
@@ -292,7 +288,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 5,
    "id": "f39b8912",
    "metadata": {},
    "outputs": [],
@@ -325,7 +321,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 6,
    "id": "eecfdc78",
    "metadata": {},
    "outputs": [],
@@ -366,7 +362,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 14,
+   "execution_count": 7,
    "id": "5b559abb",
    "metadata": {},
    "outputs": [],
@@ -410,8 +406,24 @@
     "        return END\n",
     "    \n",
     "    # Supervisor wants to rerun a node\n",
-    "    return next_agent\n",
-    "\n",
+    "    return next_agent\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "729127c9",
+   "metadata": {},
+   "source": [
+    "## Build graph"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "id": "84da69b9",
+   "metadata": {},
+   "outputs": [],
+   "source": [
     "def build_workflow_graph() -> StateGraph[AgentState]:\n",
     "    \"\"\"Builds a true pipeline architecture for Yelp Navigator.\n",
     "    \n",
@@ -483,31 +495,50 @@
     "graph = build_workflow_graph().compile()"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "88b77d8e",
+   "metadata": {},
+   "source": [
+    "## Graph Visualization\n",
+    "\n",
+    "Shows nodes, edges, conditional routing points, and feedback loops (clarification loop, supervisor revisions)."
+   ]
+  },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": 11,
    "id": "2dfa7acb",
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Could not display graph: Failed to reach https://mermaid.ink API while trying to render your graph. Status code: 400.\n",
+      "\n",
+      "To resolve this issue:\n",
+      "1. Check your internet connection and try again\n",
+      "2. Try with higher retry settings: `draw_mermaid_png(..., max_retries=5, retry_delay=2.0)`\n",
+      "3. Use the Pyppeteer rendering method which will render your graph locally in a browser: `draw_mermaid_png(..., draw_method=MermaidDrawMethod.PYPPETEER)`\n",
+      "\n",
+      "Alternatively, you can view the saved image at ./images/langgraph-supervisor.png\n"
+     ]
+    }
+   ],
    "source": [
     "# Visualize the workflow graph\n",
     "try:\n",
     "    from IPython.display import Image, display\n",
-    "    #display(Image(graph.get_graph().draw_mermaid_png()))\n",
+    "    display(Image(graph.get_graph().draw_mermaid_png()))\n",
+    "except ImportError:\n",
+    "    # Fallback: print text representation\n",
+    "    print(\"Graph visualization requires additional dependencies.\")\n",
+    "    print(\"\\nGraph structure:\")\n",
+    "    print(graph.get_graph())\n",
     "except Exception as e:\n",
     "    print(f\"Could not display graph: {e}\")\n",
-    "    print(\"\\nGraph structure:\")\n",
-    "    print(graph.get_graph())"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "88b77d8e",
-   "metadata": {},
-   "source": [
-    "## Graph Visualization\n",
-    "\n",
-    "Shows nodes, edges, conditional routing points, and feedback loops (clarification loop, supervisor revisions)."
+    "    print(\"\\nAlternatively, you can view the saved image at ./images/langgraph-supervisor.png\")"
    ]
   },
   {