In this case, you could want to document how that external API *should* look like. What *path operation* it should have, what body it should expect, what response it should return, etc.

## An app with callbacks

Let's see all this with an example.

Imagine you develop an app that allows creating invoices.

These invoices will have an `id`, `title` (optional), `customer`, and `total`.

    assertEquals("Should be able to peek() at first element", "A", peekingIterator.peek());
    assertEquals(
        "Should be able to peek() first element multiple times", "A", peekingIterator.peek());
    assertEquals(
        "next() should still return first element after peeking", "A", peekingIterator.next());

    assertEquals("Should be able to peek() at middle element", "B", peekingIterator.peek());

    assertEquals("Should be able to peek() at first element", "A", peekingIterator.peek());
    assertEquals(
        "Should be able to peek() first element multiple times", "A", peekingIterator.peek());
    assertEquals(
        "next() should still return first element after peeking", "A", peekingIterator.next());

    assertEquals("Should be able to peek() at middle element", "B", peekingIterator.peek());

  // terminating state of endpoints. This condition should be set to true for
  // a ready endpoint that is terminating. If nil, consumers should defer to
  // the ready condition.
  // +optional
  optional bool serving = 2;

  // terminating indicates that this endpoint is terminating. A nil value
  // indicates an unknown state. Consumers should interpret this unknown state
  // to mean that the endpoint is not terminating.

		t.Fatalf("no error should happen but got %v", err)
	}

	time.Sleep(time.Second)

	var result2 User
	if err := tx.Find(&result2, user.ID).Error; err != nil {
		t.Fatalf("no error should happen but got %v", err)
	}

	user2 := *GetUser("prepared_stmt2", Config{})
	if err := txCtx.Create(&user2).Error; err == nil {
		t.Fatalf("should failed to create with timeout context")
	}

                    "msg": "Input should be a valid boolean, unable to interpret input",
                    "input": "foobar",
                }
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1
        {
            "detail": [
                {
                    "loc": ["path", "item_id"],
                    "msg": "value could not be parsed to a boolean",

	}

	// RelationModel3 should be existed
	_, err = findColumnType(&RelationModel3{}, "id")
	AssertEqual(t, nil, err)

	// RelationModel1 should not be existed
	_, err = findColumnType(&RelationModel1{}, "id")
	if err == nil {
		t.Errorf("RelationModel1 should not be migrated")
	}

	// RelationModel2 should not be existed
	_, err = findColumnType(&RelationModel2{}, "id")

		g.Expect(objs.kind(name.HPAStr).size()).Should(Equal(3))
		g.Expect(objs.kind(name.PDBStr).size()).Should(Equal(3))
		g.Expect(objs.kind(name.ServiceStr).labels("istio=ingressgateway").size()).Should(Equal(3))
		g.Expect(objs.kind(name.RoleStr).nameMatches(".*gateway.*").size()).Should(Equal(3))
		g.Expect(objs.kind(name.RoleBindingStr).nameMatches(".*gateway.*").size()).Should(Equal(3))

  //   where the endpoint is located. This should match the corresponding
  //   node label.
  // * topology.kubernetes.io/zone: the value indicates the zone where the
  //   endpoint is located. This should match the corresponding node label.
  // * topology.kubernetes.io/region: the value indicates the region where the
  //   endpoint is located. This should match the corresponding node label.

glob "*stdlib/*minor" are treated specially. They should be in subdirectories
corresponding to standard library package paths, and headings for those package
paths will be generated automatically.

Files in this repo's `api/next` directory must have corresponding files in
`doc/next/*stdlib/*minor`.
The files should be in the subdirectory for the package with the new
API, and should be named after the issue number of the API proposal.