}
	return &SMA{
		buf:    make([]float64, ln),
		window: ln,
		idx:    0,
	}
}

func (s *SMA) addSample(next float64) {
	prev := s.buf[s.idx]
	s.buf[s.idx] = next

	if s.filledBuf {
		s.prevSMA += (next - prev) / float64(s.window)
		s.CAvg += (next - s.CAvg) / float64(s.window)
	} else {
		s.CAvg = s.simpleMovingAvg()
		s.prevSMA = s.CAvg
	}
	if s.idx == s.window-1 {

    /**
     *
     */
    @Test
    public void test() {
        final SingleValueIterator<String> it = new SingleValueIterator<String>("Foo");
        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is("Foo"));
        assertThat(it.hasNext(), is(not(true)));
    }

    EnumBiMap<Currency, Country> bimap = EnumBiMap.create(map);

    Iterator<Currency> iter = bimap.keySet().iterator();
    assertEquals(Currency.DOLLAR, iter.next());
    assertEquals(Currency.FRANC, iter.next());
    iter.remove();

    // forward map ordered by currency
    assertThat(bimap.keySet()).containsExactly(Currency.DOLLAR, Currency.PESO).inOrder();

        void testDecodeMisalignedCompound() {
            byte[] buffer = createMisalignedCompoundMessage();
            TestServerMessageBlock2 next = new TestServerMessageBlock2(mockConfig);
            testMessage.setNext(next);
            testMessage.setBytesRead(10);

            assertThrows(SMBProtocolDecodingException.class, () -> {
                testMessage.decode(buffer, 0);
            });

      String nextSeparator = "";
      StringBuilder builder = new StringBuilder(32).append(className).append('{');
      for (ValueHolder valueHolder = holderHead.next;
          valueHolder != null;
          valueHolder = valueHolder.next) {
        Object value = valueHolder.value;
        if (valueHolder instanceof UnconditionalValueHolder
            || (value == null
                ? !omitNullValuesSnapshot

    map.put(2, "b");
    Iterator<Entry<String, Integer>> inverseEntryItr = map.inverse().entrySet().iterator();
    Entry<String, Integer> entry = inverseEntryItr.next();
    entry.setValue(3);
    assertEquals(immutableEntry("b", 2), inverseEntryItr.next());
    assertFalse(inverseEntryItr.hasNext());
    assertThat(map.entrySet())
        .containsExactly(immutableEntry(2, "b"), immutableEntry(3, "a"))
        .inOrder();

): List<T> {
  val ia = a.iterator()
  val ib = b.iterator()

  return buildList {
    while (ia.hasNext() || ib.hasNext()) {
      if (ia.hasNext()) {
        add(ia.next())
      }
      if (ib.hasNext()) {
        add(ib.next())
      }
    }
  }

The only new thing is the `callbacks=invoices_callback_router.routes` as an argument to the *path operation decorator*. We'll see what that is next.

## Documenting the callback { #documenting-the-callback }

The actual callback code will depend heavily on your own API app.

And it will probably vary a lot from one app to the next.

It could be just one or two lines of code, like:

```Python
callback_url = "https://example.com/api/v1/invoices/events/"

/// info

If you are using containers, for example with Docker or Kubernetes, I'll tell you more about that in the next chapter: [FastAPI in Containers - Docker](docker.md){.internal-link target=_blank}.

   * position to the next in a series of predetermined positions along the printing line.
   * (Applicable also to display devices and the skip function on punched cards.)
   *
   * @since 8.0
   */
  public static final byte HT = 9;

  /**
   * Line Feed ('\n'): A format effector which controls the movement of the printing position to the