Allow the regular openai class to be used for ChatGPT models (#1393)

Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>

.gitignore

@@ -106,6 +106,7 @@ celerybeat.pid
 
 # Environments
 .env
+.envrc
 .venv
 .venvs
 env/

langchain/llms/openai.py

@@ -161,6 +161,12 @@ class BaseOpenAI(BaseLLM, BaseModel):
     streaming: bool = False
     """Whether to stream the results or not."""
 
+    def __new__(cls, **data: Any) -> Union[OpenAIChat, BaseOpenAI]:  # type: ignore
+        """Initialize the OpenAI object."""
+        if data.get("model_name", "").startswith("gpt-3.5-turbo"):
+            return OpenAIChat(**data)
+        return super().__new__(cls)
+
     class Config:
         """Configuration for this pydantic object."""
 

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "langchain"
-version = "0.0.99"
+version = "0.0.100"
 description = "Building applications with LLMs through composability"
 authors = []
 license = "MIT"

tests/integration_tests/llms/test_openai.py

@@ -144,6 +144,13 @@ async def test_openai_async_streaming_callback() -> None:
     assert isinstance(result, LLMResult)
 
 
+def test_openai_chat_wrong_class() -> None:
+    """Test OpenAIChat with wrong class still works."""
+    llm = OpenAI(model_name="gpt-3.5-turbo")
+    output = llm("Say foo:")
+    assert isinstance(output, str)
+
+
 def test_openai_chat() -> None:
     """Test OpenAIChat."""
     llm = OpenAIChat(max_tokens=10)