create().isEmpty();
    create().iterator();
    create().remove("foo");
    create().removeAll(ImmutableList.of("foo"));
    create().retainAll(ImmutableList.of("foo"));
    create().size();
    create().toArray();
    create().toArray(new String[] {"foo"});
    create().addFirst("e");
    create().addLast("e");
    create().offerFirst("e");
    create().offerLast("e");
    create().removeFirst();

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[9] *}

In this case, **FastAPI** won't ever touch or care about `__init__`, we will use it directly in our code.

## Create an instance { #create-an-instance }

We could create an instance of this class with:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[18] *}

            ContiguousSet.create(Range.closed(1, 3), integers()),
            ContiguousSet.closed(1, 3),
            ContiguousSet.create(Range.closedOpen(1, 4), integers()),
            ContiguousSet.closedOpen(1, 4),
            ContiguousSet.create(Range.openClosed(0, 3), integers()),
            ContiguousSet.create(Range.open(0, 4), integers()),
            ContiguousSet.create(Range.closed(1, 3), NOT_EQUAL_TO_INTEGERS),

    Multiset<String> c = HashMultiset.create();
    Multiset<String> multiset = ImmutableSortedMultiset.copyOf(c);
    assertTrue(multiset.isEmpty());
  }

  public void testCopyOf_multiset_oneElement() {
    Multiset<String> c = HashMultiset.create(asList("a"));
    Multiset<String> multiset = ImmutableSortedMultiset.copyOf(c);
    assertEquals(HashMultiset.create(asList("a")), multiset);
  }

        () -> EnumBiMap.create(EnumHashBiMap.<Currency, Country>create(Currency.class)));

    /* Map can be empty if it's an EnumBiMap. */
    Map<Currency, Country> emptyBimap = EnumBiMap.create(Currency.class, Country.class);
    bimap = EnumBiMap.create(emptyBimap);
    assertTrue(bimap.isEmpty());
  }

  public void testEnumBiMapConstructor() {
    /* Test that it copies existing entries. */

                        keys ->
                            path.create(transform(keys, key -> immutableEntry(key, new Object()))),
                        keys ->
                            path.create(transform(keys, key -> immutableEntry(new Object(), key))),
                        keys -> path.create(transform(keys, key -> immutableEntry(key, key)))))
            .collect(toImmutableList()),

		t.Errorf("user should be created with search value")
	}

	DB.FirstOrCreate(&user3, map[string]interface{}{"name": "find or create 2"})
	if user3.Name != "find or create 2" || user3.ID == 0 {
		t.Errorf("user should be created with inline search value")
	}

	DB.Where(&User{Name: "find or create 3"}).Attrs("age", 44).FirstOrCreate(&user4)

  public void testHoldsLockOnAllOperations() {
    create().element();
    create().offer("foo");
    create().peek();
    create().poll();
    create().remove();
    create().add("foo");
    create().addAll(ImmutableList.of("foo"));
    create().clear();
    create().contains("foo");
    create().containsAll(ImmutableList.of("foo"));
    create().equals(new ArrayDeque<>(ImmutableList.of("foo")));

    return new TestStringMultisetGenerator() {
      @Override
      protected Multiset<String> create(String[] elements) {
        Multiset<String> multiset1 = LinkedHashMultiset.create();
        Multiset<String> multiset2 = LinkedHashMultiset.create();
        for (int i = 0; i < elements.length; i++) {
          String element = elements[i];

    pass


@app.post("/invoices/", callbacks=invoices_callback_router.routes)
def create_invoice(invoice: Invoice, callback_url: Union[HttpUrl, None] = None):
    """
    Create an invoice.

    This will (let's imagine) let the API user (some external developer) create an
    invoice.

    And this path operation will:

    * Send the invoice to the client.
    * Collect the money from the client.