fix(pin pydantic version):

langcorn/server/api.py

@@ -5,25 +5,13 @@
 
 from fastapi import Depends, FastAPI, Header, HTTPException, Request
 from fastapi.security.utils import get_authorization_scheme_param
-from langchain.schema import messages_from_dict, messages_to_dict
+from langchain.callbacks import get_openai_callback
 from langchain.chains.base import Chain
+from langchain.schema import messages_from_dict, messages_to_dict
 from loguru import logger
 from pydantic import BaseModel
 from uvicorn.importer import import_from_string
 
-if sys.version_info < (3, 10):
-    # Broken in 3.9: https://github.com/msoedov/langcorn/actions/runs/6773166265/job/18407381002
-    class get_openai_callback:
-        def __enter__(self):
-            return
-
-        def __exit__(self, exc_type, exc_val, exc_tb):
-            return
-
-else:
-    from langchain.callbacks import get_openai_callback
-
-
 TRACK_USAGE = True
 
 # TODO: improve logging

pyproject.toml

@@ -26,6 +26,7 @@ bs4 = "0.0.1"                      # required for ex4.py
 langchain-experimental = "^0.0.37"
 certifi = "^2023.7.22"
 numexpr = "^2.8.7"
+pydantic = "^1.10.13"
 
 [tool.poetry.group.dev.dependencies]
 black = "^23.10.1"