{* ../../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] *}

        // Arrange
        stubAcquireReturnsSelf();
        List<FileEntry[]> pages = List.of(new FileEntry[][] { new FileEntry[] {} });

        // Create iterator where open() returns null by giving null initial
        TestIterator it = TestIterator.create(tree, parent, "*", null, 0, null, pages);

        // Assert
        assertFalse(it.hasNext(), "No next when opened with null initial");

	}

	if err := DB.Exec("CREATE EXTENSION IF NOT EXISTS pgcrypto;").Error; err != nil {
		t.Errorf("Failed to create extension pgcrypto, got error %v", err)
	}

	DB.Migrator().DropTable(&Yasuo{})

	if err := DB.AutoMigrate(&Yasuo{}); err != nil {
		t.Fatalf("Failed to migrate for uuid default value, got error: %v", err)
	}

	yasuo := Yasuo{Name: "jinzhu"}
	if err := DB.Create(&yasuo).Error; err != nil {

  public Test testsForEmptyList() {
    return ListTestSuiteBuilder.using(
            new TestStringListGenerator() {
              @Override
              public List<String> create(String[] elements) {
                return emptyList();
              }
            })
        .named("emptyList")
        .withFeatures(CollectionFeature.SERIALIZABLE, CollectionSize.ZERO)

  public Test testsForEmptyList() {
    return ListTestSuiteBuilder.using(
            new TestStringListGenerator() {
              @Override
              public List<String> create(String[] elements) {
                return emptyList();
              }
            })
        .named("emptyList")
        .withFeatures(CollectionFeature.SERIALIZABLE, CollectionSize.ZERO)

      assertThrows(NullPointerException.class, () -> table.put("bar", 1, nullableCellValue(null)));
    }
  }

  public void testPutAllTable() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    Table<String, Integer, @NonNull C> other = HashBasedTable.create();
    other.put("foo", 1, cellValue('d'));
    other.put("bar", 2, cellValue('e'));
    other.put("cat", 2, cellValue('f'));
    table.putAll(other);

    new EqualsTester()
        .addEqualityGroup(
            RemovalNotification.create("one", 1, RemovalCause.EXPLICIT),
            RemovalNotification.create("one", 1, RemovalCause.REPLACED))
        .addEqualityGroup(RemovalNotification.create("1", 1, RemovalCause.EXPLICIT))
        .addEqualityGroup(RemovalNotification.create("one", 2, RemovalCause.EXPLICIT))
        .testEquals();
  }

    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.

	}

	if err := DB.Exec("CREATE EXTENSION IF NOT EXISTS pgcrypto;").Error; err != nil {
		t.Errorf("Failed to create extension pgcrypto, got error %v", err)
	}

	DB.Migrator().DropTable(&Yasuo{})

	if err := DB.AutoMigrate(&Yasuo{}); err != nil {
		t.Fatalf("Failed to migrate for uuid default value, got error: %v", err)
	}

	yasuo := Yasuo{Name: "jinzhu"}
	if err := DB.Create(&yasuo).Error; err != nil {

    new EqualsTester()
        .addEqualityGroup(
            RemovalNotification.create("one", 1, RemovalCause.EXPLICIT),
            RemovalNotification.create("one", 1, RemovalCause.REPLACED))
        .addEqualityGroup(RemovalNotification.create("1", 1, RemovalCause.EXPLICIT))
        .addEqualityGroup(RemovalNotification.create("one", 2, RemovalCause.EXPLICIT))
        .testEquals();
  }