abort(400)

if __name__ == '__main__':
	app.run()
```

When you're writing a Lambda function for use with MinIO, the function is based on event context that MinIO provides to the Lambda function. The event context provides information about the request being made. It contains the parameters with relevant context. The fields used to create the Lambda function are as follows:

!!! tip
    You'll see what other "things", apart from functions, can be used as dependencies in the next chapter.

Whenever a new request arrives, **FastAPI** will take care of:

* Calling your dependency ("dependable") function with the correct parameters.
* Get the result from your function.
* Assign that result to the parameter in your *path operation function*.

```mermaid
graph TB

    rect rgba(0, 255, 0, .1)
        code ->> function: say_hi(name="Camila")
        function ->> execute: führe Code der Funktion aus
        execute ->> code: gib das Resultat zurück
    end

    rect rgba(0, 255, 255, .1)
        code ->> function: say_hi(name="Camila")
        function ->> code: gib das gespeicherte Resultat zurück
    end

    rect rgba(0, 255, 0, .1)

            else -> null
        }
    }

    private fun provideSourceForInvokeFunction(function: FirSimpleFunction): PsiElement? {
        val classId = function.containingClassLookupTag()?.classId ?: return null
        val classOrObject = classByClassId(classId, function.llFirSession.ktModule) ?: return null
        return classOrObject.declarations.singleOrNull()
    }

{!../../../docs_src/custom_response/tutorial008.py!}
```

1. This is the generator function. It's a "generator function" because it contains `yield` statements inside.
2. By using a `with` block, we make sure that the file-like object is closed after the generator function is done. So, after it finishes sending the response.

By default, what the method `.openapi()` does is check the property `.openapi_schema` to see if it has contents and return them.

If it doesn't, it generates them using the utility function at `fastapi.openapi.utils.get_openapi`.

And that function `get_openapi()` receives as parameters:

* `title`: The OpenAPI title, shown in the docs.
* `version`: The version of your API, e.g. `2.5.0`.

        if (!cachedCallableNames.contains(name)) return

        baseScope.processFunctionsByName(name) { function ->
            if (isTargetCallable(function)) {
                processor(function)
            }
        }
    }

    override fun processPropertiesByName(name: Name, processor: (FirVariableSymbol<*>) -> Unit) {

## Other Asynchronous Function Calls

As the testing function is now asynchronous, you can now also call (and `await`) other `async` functions apart from sending requests to your FastAPI application in your tests, exactly as you would call them anywhere else in your code.

!!! tip

# Dependencies in path operation decorators

In some cases you don't really need the return value of a dependency inside your *path operation function*.

Or the dependency doesn't return a value.

But you still need it to be executed/solved.

For those cases, instead of declaring a *path operation function* parameter with `Depends`, you can add a `list` of `dependencies` to the *path operation decorator*.

### Other utility functions

Any other utility function that you call directly can be created with normal `def` or `async def` and FastAPI won't affect the way you call it.

This is in contrast to the functions that FastAPI calls for you: *path operation functions* and dependencies.