* **Fewer bugs**: Reduce about 40% of human (developer) induced errors. *
* **Intuitive**: Great editor support. <abbr title="also known as auto-complete, autocompletion, IntelliSense">Completion</abbr> everywhere. Less time debugging.
* **Easy**: Designed to be easy to use and learn. Less time reading docs.
* **Short**: Minimize code duplication. Multiple features from each parameter declaration. Fewer bugs.

* performance: rendimiento
* program (verb): programar
* code (verb): programar
* type hints: anotaciones de tipos
* type annotations: anotaciones de tipos
* autocomplete: autocompletado
* completion (in the context of autocompletion): autocompletado
* feature: funcionalidad
* sponsor: sponsor
* host (in a podcast): host
* request (as in HTTP request): request
* response (as in HTTP response): response

   * {@code schedule}, {@code scheduleAtFixedRate}, and {@code scheduleWithFixedDelay}. In the case
   * of tasks submitted by {@code invokeAll} or {@code invokeAny}, tasks will run serially on the
   * calling thread. Tasks are run to completion before a {@code Future} is returned to the caller
   * (unless the executor has been shutdown).
   *
   * <p>The returned executor is backed by the executor returned by {@link

                    .highlighter(new ReplHighlighter())
                    .completer(systemRegistry.completer())
                    .parser(parser)
                    .variable(LineReader.LIST_MAX, 50) // max tab completion candidates
                    .variable(LineReader.HISTORY_FILE, history)
                    .variable(LineReader.OTHERS_GROUP_NAME, "Others")
                    .variable(LineReader.COMPLETION_STYLE_GROUP, "fg:blue,bold")

	return "Bucket exists: " + e.Bucket
}

// InvalidUploadIDKeyCombination - invalid upload id and key marker combination.
type InvalidUploadIDKeyCombination struct {
	UploadIDMarker, KeyMarker string
}

func (e InvalidUploadIDKeyCombination) Error() string {
	return fmt.Sprintf("Invalid combination of uploadID marker '%s' and marker '%s'", e.UploadIDMarker, e.KeyMarker)
}

![editor support](https://fastapi.tiangolo.com/img/vscode-completion.png)

* <a href="https://www.jetbrains.com/pycharm/" class="external-link" target="_blank">PyCharm</a>에서:

![editor support](https://fastapi.tiangolo.com/img/pycharm-completion.png)

여러분이 이전에 불가능하다고 고려했던 코드도 완성할 수 있을 겁니다. 예를 들어, 요청에서 전달되는 (중첩될 수도 있는)JSON 본문 내부에 있는 `price` 키입니다.

      return toString;
    }
  }

  /**
   * Returns a {@code Comparator<Boolean>} that sorts {@code true} before {@code false}.
   *
   * <p>This is particularly useful in Java 8+ in combination with {@code Comparator.comparing},
   * e.g. {@code Comparator.comparing(Foo::hasBar, trueFirst())}.
   *
   * @since 21.0
   */
  public static Comparator<Boolean> trueFirst() {
    return BooleanComparator.TRUE_FIRST;

      return toString;
    }
  }

  /**
   * Returns a {@code Comparator<Boolean>} that sorts {@code true} before {@code false}.
   *
   * <p>This is particularly useful in Java 8+ in combination with {@code Comparator.comparing},
   * e.g. {@code Comparator.comparing(Foo::hasBar, trueFirst())}.
   *
   * @since 21.0
   */
  public static Comparator<Boolean> trueFirst() {
    return BooleanComparator.TRUE_FIRST;

Then, you try with the old programmer's friend, editor autocompletion.

You type the first parameter of the function, `first_name`, then a dot (`.`) and then hit `Ctrl+Space` to trigger the completion.

But, sadly, you get nothing useful:

<img src="/img/python-types/image01.png">

### Add types { #add-types }

Let's modify a single line from the previous version.

import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicLong;
import org.jspecify.annotations.Nullable;

/**
 * A ThreadFactory builder, providing any combination of these features:
 *
 * <ul>
 *   <li>whether threads should be marked as {@linkplain Thread#setDaemon daemon} threads
 *   <li>a {@linkplain ThreadFactoryBuilder#setNameFormat naming format}