When the `with` block finishes, it makes sure to close the file, even if there were exceptions.

When you create a dependency with `yield`, **FastAPI** will internally create a context manager for it, and combine it with some other related tools.

### Using context managers in dependencies with `yield`

!!! warning
    This is, more or less, an "advanced" idea.

    If you are just starting with **FastAPI** you might want to skip it for now.