[Python] Why is pydantic_settings not parsing the correct dotenv file?

I have a FastAPI app written in Python. I want to have 2 environments for the app: dev and local. For managing the environments, I have kept 2 files namely .local.env and .dev.env. Also I have a standalone .env file, which I later plan to use for production purposes.

I am unable to parse a particular dot env file even after explicitly mentioning it.

My approach is to write a class as follows:

# config.py file

from pydantic_settings import BaseSettings, SettingsConfigDict

class EnvironmentSettings(BaseSettings):
APP_ENV: str
APP_DB_URL: str
# .... and so on...

# Experiment 1: no luck!
model_config = SettingsConfigDict(env_file=".local.env")

# Experiment 2: Settings priorities - still no luck!
model_config = SettingsConfigDict(env_file=(".local.env", ".env"))

# Experiment 3: using relative path of the file.
model_config = SettingsConfigDict(env_file="..//.local.env")

# Experiment 4: using absolute path of the file.
model_config = SettingsConfigDict(env_file="C:\\myproject\\.local.env")

# Experiment 5: Using the old format but not luck.
class Config:
env_file=".local.env"


In all cases it is parsing the contents of the standalone .env file every time - why?

Provided the folder structure is as follows:

myproject
|___ app
|____|___ config.py
|___.env
|___.local.env
|___.dev.env


Info: Python 3.12.8 and pydantic_settings >2.9.1

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