runnable bind how to nit (#10718)

docs/extras/expression_language/how_to/binding.ipynb

@@ -79,7 +79,12 @@
     }
    ],
    "source": [
-    "runnable = {\"equation_statement\": RunnablePassthrough()} | prompt | model.bind(stop=\"SOLUTION\") | StrOutputParser()\n",
+    "runnable = (\n",
+    "    {\"equation_statement\": RunnablePassthrough()} \n",
+    "    | prompt \n",
+    "    | model.bind(stop=\"SOLUTION\") \n",
+    "    | StrOutputParser()\n",
+    ")\n",
     "print(runnable.invoke(\"x raised to the third plus seven equals 12\"))"
    ]
   },
@@ -147,10 +152,11 @@
     "        (\"human\", \"{equation_statement}\")\n",
     "    ]\n",
     ")\n",
+    "model = ChatOpenAI(model=\"gpt-4\", temperature=0).bind(function_call={\"name\": \"solver\"}, functions=functions)\n",
     "runnable = (\n",
     "    {\"equation_statement\": RunnablePassthrough()} \n",
     "    | prompt \n",
-    "    | ChatOpenAI(model=\"gpt-4\", temperature=0).bind(function_call={\"name\": \"solver\"}, functions=functions)\n",
+    "    | model\n",
     ")\n",
     "runnable.invoke(\"x raised to the third plus seven equals 12\")"
    ]