import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import org.jspecify.annotations.Nullable;

/**
 * Utility class for converting between various ASCII case formats. Behavior is undefined for
 * non-ASCII input.
 *
 * @author Mike Bostock
 * @since 1.0
 */
@GwtCompatible
public enum CaseFormat {
  /**

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import org.jspecify.annotations.Nullable;

/**
 * Utility class for converting between various ASCII case formats. Behavior is undefined for
 * non-ASCII input.
 *
 * @author Mike Bostock
 * @since 1.0
 */
@GwtCompatible
public enum CaseFormat {
  /**

 * This class provides methods for converting binary data to readable hex format.
 */

public class Hexdump {

    /**
     * Default constructor.
     */
    public Hexdump() {
        // Utility class - no instance variables to initialize
    }

    /**
     * Array of hexadecimal digit characters used for converting binary data to hex representation.
     */

    En este caso, es una lista de dataclasses `Item`.

6. Aquí estamos regresando un diccionario que contiene `items`, que es una lista de dataclasses.

    FastAPI todavía es capaz de <abbr title="converting the data to a format that can be transmitted">serializar</abbr> los datos a JSON.

7. Aquí el `response_model` está usando una anotación de tipo de una lista de dataclasses `Author`.

```JSON
{"item_id":3}
```

/// check

👀 👈 💲 👆 🔢 📨 (& 📨) `3`, 🐍 `int`, 🚫 🎻 `"3"`.

, ⏮️ 👈 🆎 📄, **FastAPI** 🤝 👆 🏧 📨 <abbr title="converting the string that comes from an HTTP request into Python data">"✍"</abbr>.

///

## 💽 🔬

 */
package jcifs.util;

import jcifs.Encodable;

/**
 * Interface for objects that can be encoded to byte arrays.
 * Provides standardized method for converting objects to their binary representation.
 *
 * @author mbechler
 */
public class ByteEncodable implements Encodable {

    private final byte[] bytes;
    private final int off;
    private final int len;

Because **FastAPI** doesn't make any changes to a `Response` you return, you have to make sure its contents are ready for it.

For example, you cannot put a Pydantic model in a `JSONResponse` without first converting it to a `dict` with all the data types (like `datetime`, `UUID`, etc) converted to JSON-compatible types.

For those cases, you can use the `jsonable_encoder` to convert your data before passing it to a response:

* `frozenset`:
    * In requests and responses, treated the same as a `set`:
        * In requests, a list will be read, eliminating duplicates and converting it to a `set`.
        * In responses, the `set` will be converted to a `list`.
        * The generated schema will specify that the `set` values are unique (using JSON Schema's `uniqueItems`).
* `bytes`:

    ]
}
```

## Recap { #recap }

Declare headers with `Header`, using the same common pattern as `Query`, `Path` and `Cookie`.

{"item_id":3}
```

/// check

Notice that the value your function received (and returned) is `3`, as a Python `int`, not a string `"3"`.

So, with that type declaration, **FastAPI** gives you automatic request <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr>.

///

## Data validation { #data-validation }