{"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 }

{"item_id":3}
```

/// check | Revisa

Nota que el valor que tu función recibió (y devolvió) es `3`, como un `int` de Python, no un string `"3"`.

Entonces, con esa declaración de tipo, **FastAPI** te ofrece <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr> automático de requests.

///

## Validación de datos

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import org.jspecify.annotations.Nullable;

/**
 * Abstract {@link Hasher} that handles converting primitives to bytes using a scratch {@code
 * ByteBuffer} and streams all bytes to a sink to compute the hash.
 *
 * @author Colin Decker
 */
abstract class AbstractByteHasher extends AbstractHasher {

4️⃣. `Author` 🎻 ⚙️ `response_model` 🔢.

5️⃣. 👆 💪 ⚙️ 🎏 🐩 🆎 ✍ ⏮️ 🎻 📨 💪.

    👉 💼, ⚫️ 📇 `Item` 🎻.

6️⃣. 📥 👥 🛬 📖 👈 🔌 `items` ❔ 📇 🎻.

    FastAPI 🎯 <abbr title="converting the data to a format that can be transmitted">✍</abbr> 💽 🎻.

7️⃣. 📥 `response_model` ⚙️ 🆎 ✍ 📇 `Author` 🎻.

    🔄, 👆 💪 🌀 `dataclasses` ⏮️ 🐩 🆎 ✍.

8️⃣. 👀 👈 👉 *➡ 🛠️ 🔢* ⚙️ 🥔 `def` ↩️ `async def`.

import org.opensearch.search.SearchHit;

/**
 * Utility class for search engine operations and content formatting.
 * Provides helper methods for working with XContent builders, scrolling through search results,
 * and converting XContent objects to different output formats.
 */
public final class SearchEngineUtil {

    private static final Logger logger = LogManager.getLogger(SearchEngineUtil.class);

    /**

     */
    public RankFusionSearcher() {
        // Default constructor - name will be initialized lazily
    }

    /**
     * Returns the name of this searcher.
     * The name is derived from the class name by converting it to lowercase
     * and removing the "Searcher" suffix.
     *
     * @return the searcher name
     */
    public String getName() {
        if (name == null) {

  public void testBigToDouble() {
    for (BigInteger b : ALL_BIGINTEGER_CANDIDATES) {
      if (b.doubleValue() != DoubleUtils.bigToDouble(b)) {
        failFormat(
            "Converting %s to double: expected doubleValue %s but got bigToDouble %s",
            b, b.doubleValue(), DoubleUtils.bigToDouble(b));
      }
    }
  }

  public void testEnsureNonNegative() {

    val cookie = cookies[0]
    assertThat(cookie.name).isEqualTo("a")
    assertThat(cookie.value).isEqualTo("android")
    assertThat(cookie.commentURL).isNull()
    assertThat(cookie.discard).isFalse()
    // Converting to a fixed date can cause rounding!
    assertThat(cookie.maxAge.toDouble()).isCloseTo(60.0, 5.0)
    assertThat(cookie.path).isEqualTo("/path")
    assertThat(cookie.secure).isTrue()
  }

  @Test

    In this case, it's a list of `Item` dataclasses.

6. Here we are returning a dictionary that contains `items` which is a list of dataclasses.

    FastAPI is still capable of <abbr title="converting the data to a format that can be transmitted">serializing</abbr> the data to JSON.

7. Here the `response_model` is using a type annotation of a list of `Author` dataclasses.

Taking data from:

* The path as parameters.
* Headers.
* Cookies.
* etc.

And by doing so, **FastAPI** is validating that data, converting it and generating documentation for your API automatically.

But there are situations where you might need to access the `Request` object directly.

## Details about the `Request` object { #details-about-the-request-object }