*
   * @param string the string to test and possibly return
   * @return {@code string} if it is not null; {@code ""} otherwise
   */
  static String nullToEmpty(@Nullable String string) {
    return (string == null) ? "" : string;
  }

  /**
   * Returns the string if it is not empty, or a null string otherwise.
   *
   * @param string the string to test and possibly return

    } catch (re: RuntimeException) {
      // Happens with non-robolectric unit tests
      System.err.println("Possibly running android unit test without robolectric")
      re.printStackTrace()
    } catch (ule: UnsatisfiedLinkError) {
      // Happens with Paparazzi - with Android classes on the classpath
      System.err.println("Possibly running android unit test without robolectric")
      ule.printStackTrace()
    }
  }

/**
 * {@link Error} variant of {@link java.util.concurrent.ExecutionException}. As with {@code
 * ExecutionException}, the error's {@linkplain #getCause() cause} comes from a failed task,
 * possibly run in another thread. That cause should itself be an {@code Error}; if not, use {@code
 * ExecutionException} or {@link UncheckedExecutionException}. This allows the client code to

```Python
commons: Annotated[CommonQueryParams, Depends(CommonQueryParams)]
```

////

//// tab | Python 3.10+ non-Annotated

/// tip | Dica

Utilize a versão com `Annotated` se possível.

///

```Python
commons: CommonQueryParams = Depends(CommonQueryParams)
```

////

O último `CommonQueryParams`, em:

```Python
... Depends(CommonQueryParams)
```

/**
 * Interface for a supplier of streams that can report whether a stream was opened and whether that
 * stream was closed. Intended for use in a test where only a single stream should be opened and
 * possibly closed.
 *
 * @author Colin Decker
 */
@NullUnmarked
public interface TestStreamSupplier {

  /** Returns whether or not a new stream was opened. */
  boolean wasStreamOpened();

/**
 * Interface for a supplier of streams that can report whether a stream was opened and whether that
 * stream was closed. Intended for use in a test where only a single stream should be opened and
 * possibly closed.
 *
 * @author Colin Decker
 */
@NullUnmarked
public interface TestStreamSupplier {

  /** Returns whether or not a new stream was opened. */
  boolean wasStreamOpened();

Al usar solo `BackgroundTasks` (y no `BackgroundTask`), es posible usarla como un parámetro de *path operation function* y dejar que **FastAPI** maneje el resto por ti, tal como cuando usas el objeto `Request` directamente.

Todavía es posible usar `BackgroundTask` solo en FastAPI, pero debes crear el objeto en tu código y devolver una `Response` de Starlette incluyéndolo.

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial008b_py310.py!}
```

Isso significa que `item` pode ser um `int` ou um `str`.

#### Possivelmente `None` { #possibly-none }

Você pode declarar que um valor pode ter um tipo, como `str`, mas que ele também pode ser `None`.

//// tab | Python 3.10+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}

   *     does nothing
   * @since 17.0
   */
  public static void closeQuietly(@Nullable InputStream inputStream) {
    try {
      close(inputStream, true);
    } catch (IOException impossible) {
      throw new AssertionError(impossible);
    }
  }

  /**
   * Closes the given {@link Reader}, logging any {@code IOException} that's thrown rather than
   * propagating it.
   *

Dependencies for groups of *path operations* { #dependencies-for-groups-of-path-operations }

Later, when reading about how to structure bigger applications ([Bigger Applications - Multiple Files](../../tutorial/bigger-applications.md)), possibly with multiple files, you will learn how to declare a single `dependencies` parameter for a group of *path operations*....