tx := DB.Begin()

	user := *GetUser("transaction-save-point", Config{})
	tx.Create(&user)

	if err := tx.First(&User{}, "name = ?", user.Name).Error; err != nil {
		t.Fatalf("Should find saved record")
	}

	if err := tx.SavePoint("save_point1").Error; err != nil {
		t.Fatalf("Failed to save point, got error %v", err)
	}

	user1 := *GetUser("transaction-save-point-1", Config{})
	tx.Create(&user1)

* It should probably have a declaration of the body it should receive, e.g. `body: InvoiceEvent`.
* And it could also have a declaration of the response it should return, e.g. `response_model=InvoiceEventReceived`.

{* ../../docs_src/openapi_callbacks/tutorial001.py hl[16:18,21:22,28:32] *}

There are 2 main differences from a normal *path operation*:

In fact, in some cases, it will even have **two JSON Schemas** in OpenAPI for the same Pydantic model, for input and output, depending on if they have **default values**.

Let's see how that works and how to change it if you need to do that.

## Pydantic Models for Input and Output { #pydantic-models-for-input-and-output }

Let's say you have a Pydantic model with default values, like this one:

But you still need to use `Path` for the `item_id` path parameter. And you don't want to use `Annotated` for some reason.

Python will complain if you put a value with a "default" before a value that doesn't have a "default".

But you can re-order them, and have the value without a default (the query parameter `q`) first.

      try {
        new NullPointerTester().testMethodParameter(new OneArg(), method, 0);
      } catch (AssertionError unexpected) {
        throw new AssertionError("Should not have flagged method " + methodName, unexpected);
      }
    }
  }

  public void testStaticOneArgMethodsThatShouldFail() throws Exception {
    for (String methodName : STATIC_ONE_ARG_METHODS_SHOULD_FAIL) {

 */
@Deprecated
public interface ArtifactTransformationManager {
    String ROLE = ArtifactTransformationManager.class.getName();

    /**
     * Take in an artifact and return the transformed artifact for locating in the remote repository. If no
     * transformation has occurred the original artifact is returned.
     *
     * @param artifact           Artifact to be transformed.

Let's say you have a file structure as described in [Bigger Applications](bigger-applications.md){.internal-link target=_blank}:

```
.
├── app
│   ├── __init__.py
│   └── main.py
```

In the file `main.py` you have your **FastAPI** app:


{* ../../docs_src/app_testing/main.py *}

### Testing file { #testing-file }

  /*
   * Ideally, this class would have exposed only constructors that require a non-null cause. See
   * https://github.com/jspecify/jspecify-reference-checker/blob/61aafa4ae52594830cfc2d61c8b113009dbdb045/src/main/java/com/google/jspecify/nullness/NullSpecTransfer.java#L789
   * and https://github.com/jspecify/jspecify/issues/490.
   *
   * (That would also have ensured that its cause was always an Error, rather than possibly another

		t.Error(err)
	}

	lvl := &Level3{}
	if err := DB.Save(lvl).Error; err != nil {
		t.Error(err)
	}

	sublvl1 := &Level4{Level3ID: lvl.ID}
	if err := DB.Save(sublvl1).Error; err != nil {
		t.Error(err)
	}
	sublvl2 := &Level4{Level3ID: lvl.ID}
	if err := DB.Save(sublvl2).Error; err != nil {
		t.Error(err)
	}

	lvl.Level4s = []*Level4{sublvl1, sublvl2}

{* ../../docs_src/dependencies/tutorial008_an_py39.py hl[18:19,26:27] *}

The same way, you could have some dependencies with `yield` and some other dependencies with `return`, and have some of those depend on some of the others.

And you could have a single dependency that requires several other dependencies with `yield`, etc.

You can have any combinations of dependencies that you want.