[Python] FastAPI throws an error (Error loading ASGI app. Could not import module "api")

I tried to run FastAPI using uvicorn webserver but it throws an error.

I run this command,

uvicorn api:app --reload --host 0.0.0.0


but there is an error in the terminal.

Uvicorn running on http://0.0.0.0:8000 (Press CTRL+C to quit)
Started reloader process [23445]
Error loading ASGI app. Could not import module "api".
Stopping reloader process [23445]

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