## A "callable" instance { #a-callable-instance }

In Python there's a way to make an instance of a class a "callable".

Not the class itself (which is already a callable), but an instance of that class.

To do that, we declare a method `__call__`:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[12] *}

  private long currentTimeNanos() {
    return ticker.read();
  }

  private void alertListenerIfPresent(K key, V value, RemovalCause cause) {
    if (removalListener != null) {
      removalListener.onRemoval(RemovalNotification.create(key, value, cause));
    }
  }

  @SuppressWarnings("GoodTime") // timestamps as numeric primitives
  private V load(K key) throws ExecutionException {

      try {
        stimuli[i].executeAndCompare(reference, target);
        verify(reference.getElements());
      } catch (AssertionError cause) {
        throw new AssertionError("failed with stimuli " + subListCopy(stimuli, i + 1), cause);
      }
    }
  }

  private static List<Object> subListCopy(Object[] source, int size) {
    Object[] copy = new Object[size];

	data, err := io.ReadAll(body)
	if err != nil {
		return SRError{
			Cause: err,
			Code:  ErrSiteReplicationInvalidRequest,
		}
	}
	if encryptionKey != "" {
		data, err = madmin.DecryptData(encryptionKey, bytes.NewReader(data))
		if err != nil {
			return SRError{
				Cause: err,
				Code:  ErrSiteReplicationInvalidRequest,
			}
		}
	}
	return json.Unmarshal(data, v)

        UnsupportedOperationException ex = assertThrows(UnsupportedOperationException.class, it::remove);
        assertEquals("remove", ex.getMessage());
    }

    @Nested
    @DisplayName("Invalid constructor inputs")
    class InvalidInputs {
        @Test
        @DisplayName("Null delegate causes NullPointerException during construction")
        void nullDelegate_throwsNPE() throws Exception {

SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

   * value} before proceeding with the {@link #put} operation. If the bimap previously contained the
   * provided key-value mapping, this method has no effect.
   *
   * <p>Note that a successful call to this method could cause the size of the bimap to increase by
   * one, stay the same, or even decrease by one.
   *
   * <p><b>Warning:</b> If an existing entry with this value is removed, the key for that entry is
   * discarded and not returned.

  @Synchronized override fun close() {
    executor.shutdown()
    socket?.closeQuietly()
    serverSocket?.closeQuietly()
  }

  override fun toString(): String = "MockHttp2Peer[$port]"

  private class OutFrame(
    val sequence: Int,
    val start: Long,
    val truncated: Boolean,
  )

  class InFrame(
    val sequence: Int,
    val reader: Http2Reader,

  </description>
  <defaults>
    <default>
      <key>package</key>
      <value>org.apache.maven.artifact.repository.metadata</value>
    </default>
  </defaults>
  <classes>
    <class rootElement="true" xml.tagName="metadata" java.clone="deep">
      <name>Metadata</name>
      <version>1.0.0+</version>
      <fields>
        <field xml.attribute="true" xml.tagName="modelVersion">

E então outra tarefa em segundo plano gerada na _função de operação de caminho_ escreverá uma mensagem usando o parâmetro de caminho `email`.

## Detalhes técnicos

A classe `BackgroundTasks` vem diretamente de <a href="https://www.starlette.io/background/" class="external-link" target="_blank">`starlette.background`</a>.