experimental[minor]: Add bind_tools and with_structured_output functions to OllamaFunctions (#20881)

Implemented bind_tools for OllamaFunctions.
Made OllamaFunctions sub class of ChatOllama.
Implemented with_structured_output for OllamaFunctions.

integration unit test has been updated.
notebook has been updated.

---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/experimental/tests/integration_tests/llms/test_ollama_functions.py

@@ -2,9 +2,18 @@
 
 import unittest
 
-from langchain_community.chat_models.ollama import ChatOllama
+from langchain_core.messages import AIMessage
+from langchain_core.pydantic_v1 import BaseModel, Field
 
-from langchain_experimental.llms.ollama_functions import OllamaFunctions
+from langchain_experimental.llms.ollama_functions import (
+    OllamaFunctions,
+    convert_to_ollama_tool,
+)
+
+
+class Joke(BaseModel):
+    setup: str = Field(description="The setup of the joke")
+    punchline: str = Field(description="The punchline to the joke")
 
 
 class TestOllamaFunctions(unittest.TestCase):
@@ -13,12 +22,11 @@ class TestOllamaFunctions(unittest.TestCase):
     """
 
     def test_default_ollama_functions(self) -> None:
-        base_model = OllamaFunctions(model="mistral")
-        self.assertIsInstance(base_model.model, ChatOllama)
+        base_model = OllamaFunctions(model="llama3", format="json")
 
         # bind functions
-        model = base_model.bind(
-            functions=[
+        model = base_model.bind_tools(
+            tools=[
                 {
                     "name": "get_current_weather",
                     "description": "Get the current weather in a given location",
@@ -47,3 +55,29 @@ class TestOllamaFunctions(unittest.TestCase):
         function_call = res.additional_kwargs.get("function_call")
         assert function_call
         self.assertEqual(function_call.get("name"), "get_current_weather")
+
+    def test_ollama_structured_output(self) -> None:
+        model = OllamaFunctions(model="phi3")
+        structured_llm = model.with_structured_output(Joke, include_raw=False)
+
+        res = structured_llm.invoke("Tell me a joke about cats")
+        assert isinstance(res, Joke)
+
+    def test_ollama_structured_output_with_json(self) -> None:
+        model = OllamaFunctions(model="phi3")
+        joke_schema = convert_to_ollama_tool(Joke)
+        structured_llm = model.with_structured_output(joke_schema, include_raw=False)
+
+        res = structured_llm.invoke("Tell me a joke about cats")
+        assert "setup" in res
+        assert "punchline" in res
+
+    def test_ollama_structured_output_raw(self) -> None:
+        model = OllamaFunctions(model="phi3")
+        structured_llm = model.with_structured_output(Joke, include_raw=True)
+
+        res = structured_llm.invoke("Tell me a joke about cars")
+        assert "raw" in res
+        assert "parsed" in res
+        assert isinstance(res["raw"], AIMessage)
+        assert isinstance(res["parsed"], Joke)