Create Langchain LLM converter to quickly supply it to Langchain's chain (#102)

* Create Langchain LLM converter to quickly supply it to Langchain's chain

* Clean up

tests/test_agent.py

@@ -189,7 +189,7 @@ def test_react_agent_langchain(openai_completion, llm, mock_google_search):
     langchain_plugins = [tool.to_langchain_format() for tool in plugins]
     agent = initialize_agent(
         langchain_plugins,
-        llm._obj,
+        llm.to_langchain_format(),
         agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION,
         verbose=True,
     )

tests/test_llms_chat_models.py

@@ -48,7 +48,7 @@ def test_azureopenai_model(openai_completion):
         temperature=0,
     )
     assert isinstance(
-        model._obj, AzureChatOpenAILC
+        model.to_langchain_format(), AzureChatOpenAILC
     ), "Agent not wrapped in Langchain's AzureChatOpenAI"
 
     # test for str input - stream mode

tests/test_llms_completion_models.py

@@ -41,7 +41,7 @@ def test_azureopenai_model(openai_completion):
         request_timeout=60,
     )
     assert isinstance(
-        model._obj, AzureOpenAILC
+        model.to_langchain_format(), AzureOpenAILC
     ), "Agent not wrapped in Langchain's AzureOpenAI"
 
     output = model("hello world")
@@ -64,7 +64,7 @@ def test_openai_model(openai_completion):
         request_timeout=60,
     )
     assert isinstance(
-        model._obj, OpenAILC
+        model.to_langchain_format(), OpenAILC
     ), "Agent is not wrapped in Langchain's OpenAI"
 
     output = model("hello world")