FastAPI supports dependencies that do some <abbr title='sometimes also called "exit code", "cleanup code", "teardown code", "closing code", "context manager exit code", etc.'>extra steps after finishing</abbr>.

To do this, use `yield` instead of `return`, and write the extra steps (code) after.

/// tip

Make sure to use `yield` one single time per dependency.

///

/// note | Technical Details

    So, it is a generator function that transfers the "generating" work to something else internally.

    By doing it this way, we can put it in a `with` block, and that way, ensure that the file-like object is closed after finishing.

/// tip

Notice that here as we are using standard `open()` that doesn't support `async` and `await`, we declare the path operation with normal `def`.

///

### `FileResponse` { #fileresponse }

			}
		}
		break
	}

	refreshInterval := sys.iamRefreshInterval
	go sys.periodicRoutines(ctx, refreshInterval)

	bootstrapTraceMsg("finishing IAM loading")
}

const maxDurationSecondsForLog = 5

func (sys *IAMSys) periodicRoutines(ctx context.Context, baseInterval time.Duration) {
	// Watch for IAM config changes for iamStorageWatcher.