Now you know that whenever you need them you can use them in **FastAPI**.

### Pydantic v1 `regex` instead of `pattern` { #pydantic-v1-regex-instead-of-pattern }

Before Pydantic version 2 and before FastAPI 0.100.0, the parameter was called `regex` instead of `pattern`, but it's now deprecated.

You could still see some code using it:

//// tab | Pydantic v1

* The encryption of the connection happens at the **TCP level**.
    * That's one layer **below HTTP**.
    * So, the **certificate and encryption** handling is done **before HTTP**.
* **TCP doesn't know about "domains"**. Only about IP addresses.
    * The information about the **specific domain** requested goes in the **HTTP data**.

The **server** program (for example **Uvicorn** via **FastAPI CLI**) is capable of interpreting these headers, and then passing that information to your application.

{* ../../docs_src/security/tutorial005_an_py310.py hl[5,9,13,47,65,106,108:116,122:126,130:136,141,157] *}

Now let's review those changes step by step.

## OAuth2 Security scheme { #oauth2-security-scheme }

The first change is that now we are declaring the OAuth2 security scheme with two available scopes, `me` and `items`.

    By having the type as `int | None`, SQLModel will know that this column should be an `INTEGER` in the SQL database and that it should be `NULLABLE`.

* `Field(index=True)` tells SQLModel that it should create a **SQL index** for this column, that would allow faster lookups in the database when reading data filtered by this column.

* and from it, import the function `get_token_header`.

That would refer to some package above `app/`, with its own file `__init__.py`, etc. But we don't have that. So, that would throw an error in our example. 🚨

But now you know how it works, so you can use relative imports in your own apps no matter how complex they are. 🤓

### Add some custom `tags`, `responses`, and `dependencies` { #add-some-custom-tags-responses-and-dependencies }

So you wait for your crush to finish the story (finish the current work ⏯ / task being processed 🤓), smile gently and say that you are going for the burgers ⏸.

### Generate a TypeScript Client with Custom Operation IDs { #generate-a-typescript-client-with-custom-operation-ids }

Now, if you generate the client again, you will see that it has the improved method names:

<img src="/img/tutorial/generate-clients/image07.png">

As you see, the method names now have the tag and then the function name, now they don't include information from the URL path and the HTTP operation.

     *   <li>If this field's value is some other thread object, we know that it's not our thread.
     *   <li>If this field's value == null because it originally belonged to another thread and that
     *       thread cleared it, we still know that it's not associated with our thread
     *   <li>If this field's value == null because it was associated with our thread and was
     *       cleared, we know that we're not executing inline any more
     * </ul>

* And many other things

## Conclusion { #conclusion }

If you read and understood all this, now **you know much more** about virtual environments than many developers out there. 🤓