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()
    }

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*.

The [Func] type, which represents a function or method symbol, now
has a [Func.Signature] method that returns the function's type, which

```Python hl_lines="14"
{!../../../docs_src/background_tasks/tutorial001.py!}
```

`.add_task()` receives as arguments:

* A task function to be run in the background (`write_notification`).
* Any sequence of arguments that should be passed to the task function in order (`email`).

# Advanced Dependencies

## Parameterized dependencies

All the dependencies we have seen are a fixed function or class.

But there could be cases where you want to be able to set parameters on the dependency, without having to declare many different functions or classes.

Let's imagine that we want to have a dependency that checks if the query parameter `q` contains some fixed content.

But we want to be able to parameterize that fixed content.

    Maybe you need to start a new version, or you just got tired of running it. 🤷

### Lifespan function

The first thing to notice, is that we are defining an async function with `yield`. This is very similar to Dependencies with `yield`.

```Python hl_lines="14-19"
{!../../../docs_src/events/tutorial003.py!}
```

The first part of the function, before the `yield`, will be executed **before** the application starts.

## Get the user

Now create a function that will:

* Take a username.
* Generate a document ID from it.
* Get the document with that ID.
* Put the contents of the document in a `UserInDB` model.