Remember that when you import `Query`, `Path`, and others from `fastapi`, those are actually functions that return special classes.

///

/// tip

Notice how each model's attribute with a type, default value and `Field` has the same structure as a *path operation function's* parameter, with `Field` instead of `Path`, `Query` and `Body`.

///

     *
     * @param <KEY> the key type of the <code>Map</code>
     * @param <VALUE> the value type of the <code>Map</code>
     * @param key the key to be added to the <code>Map</code>
     * @param value the value to be added to the <code>Map</code>
     * @return a {@literal Maps} for constructing a {@link Map} with the specified key and value
     */

    val tagAndClass = source.readByte().toInt() and 0xff
    val tagClass = tagAndClass and 0b1100_0000
    val constructed = (tagAndClass and 0b0010_0000) == 0b0010_0000
    val tag =
      when (val tag0 = tagAndClass and 0b0001_1111) {
        0b0001_1111 -> readVariableLengthLong()
        else -> tag0.toLong()
      }

    // Read the length.
    val length0 = source.readByte().toInt() and 0xff
    val length =
      when {

https://github.com/golang/protobuf

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

    * Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer

And the `dict` you receive as `weights` will actually have `int` keys and `float` values.

///

## Recap { #recap }

With **FastAPI** you have the maximum flexibility provided by Pydantic models, while keeping your code simple, short and elegant.

But with all the benefits:

* Editor support (completion everywhere!)

first connect fails. This is necessary for IPv4+IPv6 and services hosted in redundant data
centers. OkHttp supports modern TLS features (TLS 1.3, ALPN, certificate pinning). It can be
configured to fall back for broad connectivity.

Using OkHttp is easy. Its request/response API is designed with fluent builders and immutability. It
supports both synchronous blocking calls and async calls with callbacks.

A well behaved user agent

They're also concrete: each URL identifies a specific path (like `/square/okhttp`) and query (like `?q=sharks&lang=en`). Each webserver hosts many URLs.

### [Addresses](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-address/)

Addresses specify a webserver (like `github.com`) and all of the **static** configuration necessary to connect to that server: the port number, HTTPS settings, and preferred network protocols (like HTTP/2).

But here's the key point.

The security and dependency injection stuff is written once.

And you can make it as complex as you want. And still, have it written only once, in a single place. With all the flexibility.

But you can have thousands of endpoints (*path operations*) using the same security system.

And a response with a status code `200` that uses your `response_model`, but includes a custom `example`:

{* ../../docs_src/additional_responses/tutorial003.py hl[20:31] *}

It will all be combined and included in your OpenAPI, and shown in the API docs:

<img src="/img/tutorial/additional-responses/image01.png">

In this example, we'll use **SQLite**, because it uses a single file and Python has integrated support. So, you can copy this example and run it as is.

Later, for your production application, you might want to use a database server like **PostgreSQL**.

/// tip