* `frozenset`:
    * In requests and responses, treated the same as a `set`:
        * In requests, a list will be read, eliminating duplicates and converting it to a `set`.
        * In responses, the `set` will be converted to a `list`.

    assert response.json() == {
        "detail": [
            {
                "loc": ["path", "item_id"],
                "input": "-1",
                "msg": "Input should be greater than or equal to 0",
                "type": "greater_than_equal",
                "ctx": {"ge": 0},
            }
        ]
    }


def test_read_items_item_id_greater_than_one_thousand(client: TestClient):

{* ../../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] *}

		}

		if ok, msg := assertCallbacks(callbacks.Create(), data.results); !ok {
			t.Errorf("callbacks tests #%v failed, got %v", idx+1, msg)
		}
	}
}

func TestPluginCallbacks(t *testing.T) {
	db, _ := gorm.Open(nil, nil)
	createCallback := db.Callback().Create()

	createCallback.Before("*").Register("plugin_1_fn1", c1)

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[1,13] *}

**FastAPI** will create the object of type `BackgroundTasks` for you and pass it as that parameter.

## Create a task function { #create-a-task-function }

Create a function to be run as the background task.

It is just a standard function that can receive parameters.

---> 100%
```

</div>

**Note**: Make sure you put `"fastapi[standard]"` in quotes to ensure it works in all terminals.

## Example

### Create it

Create a file `main.py` with:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}

			testResults = append(testResults, result{dir, entries})
			t.Fatalf("Unable to create a file, %s", err)
		}
		// Symlink will not be added to entries.
		if err := os.Symlink(filepath.Join(dir, name1), filepath.Join(dir, name2)); err != nil {
			t.Fatalf("Unable to create a symlink, %s", err)
		}
		// Add to entries.
		entries = append(entries, name1)

		},
		Item2: &QueryResetItem{
			ID:   "u_2_2",
			Name: "item_2_2",
		},
	}

	var err error
	err = DB.Create(&q1).Error
	if err != nil {
		t.Errorf("failed to create:%v", err)
	}

	err = DB.Create(&q2).Error
	if err != nil {
		t.Errorf("failed to create:%v", err)
	}

	var qs []QueryResetNullValue
	err = DB.Joins("Item1").Joins("Item2").Find(&qs).Error
	if err != nil {

	if err != nil {
		t.Fatal(err)
	}

	// Create volume to use in conjunction with other StorageAPI's file API(s)
	err = fs.MakeVol(context.Background(), "voldir")
	if err != nil {
		t.Fatal(err)
	}

	err = fs.AppendFile(context.Background(), "voldir", "/file", []byte("hello"))
	if err != nil {
		t.Fatal(err)
	}

	// Try to create a file that includes a file in its path components.

    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.