### 3. Generate Self-contained Access Tokens

By default, a UUID is issued as an id_token in WSO2 Identity Server, which is of the first type above. But, it also can be configured to issue a self-contained id_token (JWT), which is of the second type above.

- Open the `<IS_HOME>/repository/conf/identity/identity.xml` file and uncomment the following entry under `<OAuth>` element.

```

	DiskID  string `msg:"id"`
	Metrics bool   `msg:"m"`
	NoOp    bool   `msg:"np"`
}

// DiskInfo is an extended type which returns current
// disk usage per path.
// The above means that any added/deleted fields are incompatible.
//
// The above means that any added/deleted fields are incompatible.
//
//msgp:tuple DiskInfo
type DiskInfo struct {
	Total      uint64
	Free       uint64
	Used       uint64
	UsedInodes uint64

    }

    /**
     * Filters JVM options based on the current Java version.
     * Options can be prefixed with version numbers to specify compatibility.
     * Format: "version:option" or "version-:option" (for version and above).
     *
     * @param values the array of JVM options to filter
     * @return the filtered array of JVM options applicable to the current Java version
     */

## About Pydantic { #about-pydantic }

Pydantic includes the tests for **FastAPI** with its own tests, so new versions of Pydantic (above `1.0.0`) are always compatible with FastAPI.

You can pin Pydantic to any version above `1.0.0` that works for you.

For example:

```txt
pydantic>=2.7.0,<3.0.0

/// info

Webhooks are available in OpenAPI 3.1.0 and above, supported by FastAPI `0.99.0` and above.

///

## An app with webhooks { #an-app-with-webhooks }

They are more relevant for older versions, before OpenAPI 3.1.0 was available.

You can consider this a brief OpenAPI and JSON Schema **history lesson**. 🤓

///

/// warning

These are very technical details about the standards **JSON Schema** and **OpenAPI**.

modification, are permitted provided that the following conditions
are met:

1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

### 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:

{* ../../docs_src/body_nested_models/tutorial002.py hl[1] *}

/// info

The parameter `summary` is available in OpenAPI 3.1.0 and above, supported by FastAPI 0.99.0 and above.

///

## Overriding the defaults { #overriding-the-defaults }

Using the information above, you can use the same utility function to generate the OpenAPI schema and override each part that you need.

async with lifespan(app):
    await do_stuff()
```

When you create a context manager or an async context manager like above, what it does is that, before entering the `with` block, it will execute the code before the `yield`, and after exiting the `with` block, it will execute the code after the `yield`.

In our code example above, we don't use it directly, but we pass it to FastAPI for it to use it.