/// tip | Dica

Para saber mais sobre cada código de status e qual código serve para quê, verifique o <a href="https://developer.mozilla.org/pt-BR/docs/Web/HTTP/Status" class="external-link" target="_blank"><abbr title="Mozilla Developer Network">MDN</abbr> documentação sobre códigos de status HTTP</a>.

///

{* ../../docs_src/query_params_str_validations/tutorial002.py hl[9] *}

Note que substituímos o valor padrão de `None` para `Query(default=None)`, o primeiro parâmetro de `Query` serve para o mesmo propósito: definir o valor padrão do parâmetro.

Então:

```Python
q: Union[str, None] = Query(default=None)
```

...Torna o parâmetro opcional, da mesma maneira que:

```Python

   * {@code lexicographical(Collections.reverseOrder(comparator))} (consider how each would order
   * {@code [1]} and {@code [1, 1]}).
   */
  // Note: 90% of the time we don't add type parameters or wildcards that serve only to "tweak" the
  // desired return type. However, *nested* generics introduce a special class of problems that we
  // think tip it over into being worthwhile.

### In a Remote Server { #in-a-remote-server }

When you set up a remote server (a cloud server, a virtual machine, etc.) the simplest thing you can do is use `fastapi run` (which uses Uvicorn) or something  similar, manually, the same way you do when developing locally.

And it will work and will be useful **during development**.

But if your connection to the server is lost, the **running process** will probably die.

    * For this to work, a **single** component (program) running on the server, listening on the **public IP address**, must have **all the HTTPS certificates** in the server.
* **After** obtaining a secure connection, the communication protocol is **still HTTP**.

		var remoteIP string

		if host, _, err := net.SplitHostPort(sconn.RemoteAddr().String()); err == nil {
			remoteIP = host
		}
		server := sftp.NewRequestServer(channel, NewSFTPDriver(sconn.Permissions, remoteIP), sftp.WithRSAllocator())
		defer server.Close()
		server.Serve()
	}

	sftpServer, err := xsftp.NewServer(&xsftp.Options{
		PublicIP: publicIP,
		Port:     port,

   <span style="background-color:#007166"><font color="#D3D7CF"> server </font></span>  Server started at <font color="#729FCF"><u style="text-decoration-style:solid">http://127.0.0.1:8000</u></font>
   <span style="background-color:#007166"><font color="#D3D7CF"> server </font></span>  Documentation at <font color="#729FCF"><u style="text-decoration-style:solid">http://127.0.0.1:8000/docs</u></font>

E esses modelos estão compartilhando muitos dos dados e duplicando nomes e tipos de atributos.

Nós poderíamos fazer melhor.

Podemos declarar um modelo `UserBase` que serve como base para nossos outros modelos. E então podemos fazer subclasses desse modelo que herdam seus atributos (declarações de tipo, validação, etc.).

Toda conversão de dados, validação, documentação, etc. ainda funcionará normalmente.

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   * java.util.IllegalFormatException}.
   *
   * <p>In certain cases, such as outputting debugging information or constructing a message to be
   * used for another unchecked exception, an exception during string formatting would serve little
   * purpose except to supplant the real information you were trying to provide. These are the cases
   * this method is made for; it instead generates a best-effort string with all supplied argument