/// tip

You can use `async` or regular functions.

**FastAPI** will do the right thing with each, the same as with normal dependencies.

///

## A dependency with `yield` and `try` { #a-dependency-with-yield-and-try }

If you use a `try` block in a dependency with `yield`, you'll receive any exception that was thrown when using the dependency.

<img src="/img/tutorial/security/image11.png">

## JWT token with scopes { #jwt-token-with-scopes }

Now, modify the token *path operation* to return the scopes requested.

We are still using the same `OAuth2PasswordRequestForm`. It includes a property `scopes` with a `list` of `str`, with each scope it received in the request.

- **5-15% faster** type conversions with pattern matching and switch expressions
- **Reduced memory allocation** in collection operations and bean copying
- **Improved reflection performance** with cached descriptors and optimized field access
- **Enhanced collection operations** with Java 21 sequenced collections support

But at the same time, functions defined with `async def` have to be "awaited". So, functions with `async def` can only be called inside of functions defined with `async def` too.

So, about the egg and the chicken, how do you call the first `async` function?

    /**
     * Test AutoCloseable implementation
     */
    @Test
    @DisplayName("Test AutoCloseable implementation with try-with-resources")
    public void testAutoCloseableImpl() {
        String testPassword = "AutoCloseablePass123!";
        NtlmPasswordAuthenticator authRef;

        // Use try-with-resources
        try (NtlmPasswordAuthenticator auth = new NtlmPasswordAuthenticator("user", testPassword)) {

But Python has a specific way to declare lists with internal types, or "type parameters":

### Import typing's `List` { #import-typings-list }

In Python 3.9 and above you can use the standard `list` to declare these type annotations as we'll see below. 💡

But in Python versions before 3.9 (3.6 and above), you first need to import `List` from standard Python's `typing` module:

### Read One Hero with `HeroPublic` { #read-one-hero-with-heropublic }

We can **read** a single hero:

{* ../../docs_src/sql_databases/tutorial002_an_py310.py ln[75:80] hl[77] *}

### Update a Hero with `HeroUpdate` { #update-a-hero-with-heroupdate }

We can **update a hero**. For this we use an HTTP `PATCH` operation.

* **X-Forwarded-Host**: The original host (`mysuperapp.com`)

When **FastAPI CLI** is configured with `--forwarded-allow-ips`, it trusts these headers and uses them, for example to generate the correct URLs in redirects.

## Proxy with a stripped path prefix { #proxy-with-a-stripped-path-prefix }

You could have a proxy that adds a path prefix to your application.

## Additional Response with `model` { #additional-response-with-model }

You can pass to your *path operation decorators* a parameter `responses`.

It receives a `dict`: the keys are status codes for each response (like `200`), and the values are other `dict`s with the information for each of them.

If you don't want to include the `standard` optional dependencies, you can install with `pip install fastapi` instead of `pip install "fastapi[standard]"`.

### Without `fastapi-cloud-cli` { #without-fastapi-cloud-cli }

If you want to install FastAPI with the standard dependencies but without the `fastapi-cloud-cli`, you can install with `pip install "fastapi[standard-no-fastapi-cloud-cli]"`.