{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## Add the background task

Inside of your *path operation function*, pass your task function to the *background tasks* object with the method `.add_task()`:

{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}

`.add_task()` receives as arguments:

* A task function to be run in the background (`write_notification`).

  EXPECT_EQ(TF_GetCode(status), TF_OK) << TF_Message(status);

  const char task0_name[] = "/job:localhost/replica:0/task:0/device:CPU:0";
  const char task1_name[] = "/job:localhost/replica:0/task:1/device:CPU:0";
  const char task2_name[] = "/job:localhost/replica:0/task:2/device:CPU:0";

  // Create one variable per task.
  TFE_TensorHandle* h0 = TestVariable(ctx, 1.0, task1_name);
  TFE_TensorHandle* h1 = TestVariable(ctx, 2.0, task2_name);

							task.event.StorageClass, task.objInfo.Bucket, task.objInfo.Name, task.objInfo.VersionID, err))
					}
				}
			} else {
				ts := tierStats{
					TotalSize:   uint64(task.objInfo.Size),
					NumVersions: 1,
				}
				if task.objInfo.IsLatest {
					ts.NumObjects = 1
				}
				t.addLastDayStats(task.event.StorageClass, ts)
			}
			t.activeTasks.Add(-1)

            logger.warn("Failed to generate a thumbnail of {}: {}", thumbnailId, commandList, e);
        }
        if (task != null && !task.isExecuted()) {
            task.cancel();
        }
    }

    protected static class ProcessDestroyer extends TimerTask {

        private final Process p;

        private final InputStreamThread ist;

        private final AtomicBoolean executed = new AtomicBoolean(false);

            directExecutor());

    // Wait for the first task to be started in the background. It will block until we explicitly
    // stop it.
    blockingCallable.waitForStart();

    // Give the second task a chance to (incorrectly) start up while the first task is running.
    assertThat(future2.isDone()).isFalse();

    // Stop the first task. The second task should then run.
    blockingCallable.stop();

  private static class FakeExecutor implements Executor {
    Queue<Runnable> tasks = Queues.newArrayDeque();

    @Override
    public void execute(Runnable command) {
      tasks.add(command);
    }

    boolean hasNext() {
      return !tasks.isEmpty();
    }

    void runNext() {
      assertTrue("expected at least one task to run", hasNext());
      tasks.remove().run();
    }

    void runAll() {

    public <T> Future<T> submit(Callable<T> task) {
      lastMethodCalled = "submit";
      assertThat(task).isInstanceOf(WrappedCallable.class);
      return inline.submit(task);
    }

    @Override
    public Future<?> submit(Runnable task) {
      lastMethodCalled = "submit";
      assertThat(task).isInstanceOf(WrappedRunnable.class);
      return inline.submit(task);
    }

    @Override

  private static class FakeExecutor implements Executor {
    Queue<Runnable> tasks = Queues.newArrayDeque();

    @Override
    public void execute(Runnable command) {
      tasks.add(command);
    }

    boolean hasNext() {
      return !tasks.isEmpty();
    }

    void runNext() {
      assertTrue("expected at least one task to run", hasNext());
      tasks.remove().run();
    }

    void runAll() {

                final Tuple3<String, String, String> task = generator.createTask(path, docMap);
                if (task != null) {
                    if (logger.isDebugEnabled()) {
                        logger.debug("Add thumbnail task: {}", task);
                    }
                    if (!thumbnailTaskQueue.offer(task)) {
                        logger.warn("Failed to add thumbnail task: {}", task);
                    }

    public <T> Future<T> submit(Callable<T> task) {
      lastMethodCalled = "submit";
      assertThat(task).isInstanceOf(WrappedCallable.class);
      return inline.submit(task);
    }

    @Override
    public Future<?> submit(Runnable task) {
      lastMethodCalled = "submit";
      assertThat(task).isInstanceOf(WrappedRunnable.class);
      return inline.submit(task);
    }

    @Override