```Python hl_lines="1 4"
{!../../../docs_src/python_types/tutorial009.py!}
```

O uso de `Opcional [str]` em vez de apenas `str` permitirá que o editor o ajude a detectar erros, onde você pode estar assumindo que um valor é sempre um `str`, quando na verdade também pode ser `None`.

#### Tipos genéricos

Esses tipos que usam parâmetros de tipo entre colchetes, como:

* `List`
* `Tuple`

	"os"
	"runtime"
	"syscall"
)

// No space left on device error
func isSysErrNoSpace(err error) bool {
	return errors.Is(err, syscall.ENOSPC)
}

// Invalid argument, unsupported flags such as O_DIRECT
func isSysErrInvalidArg(err error) bool {
	return errors.Is(err, syscall.EINVAL)
}

// Input/output error
func isSysErrIO(err error) bool {
	return errors.Is(err, syscall.EIO)
}

	MOVQ 2147483647+1(AX), AX       // ERROR "offset too large"
	MOVQ 3395469782(R10), R8        // ERROR "offset too large"
	LEAQ 3395469782(AX), AX         // ERROR "offset too large"
	ADDQ 3395469782(AX), AX         // ERROR "offset too large"
	ADDL 3395469782(AX), AX         // ERROR "offset too large"
	ADDW 3395469782(AX), AX         // ERROR "offset too large"
	LEAQ 433954697820(AX), AX       // ERROR "offset too large"

type ObjectNamePrefixAsSlash GenericError

// Error returns string an error formatted as the given text.
func (e ObjectNameInvalid) Error() string {
	return "Object name invalid: " + e.Bucket + "/" + e.Object
}

// Error returns string an error formatted as the given text.
func (e ObjectNameTooLong) Error() string {
	return "Object name too long: " + e.Bucket + "/" + e.Object
}

	var result Yasuo
	if err := DB.First(&result, "id = ?", yasuo.ID).Error; err != nil || yasuo.Name != "jinzhu" {
		t.Errorf("No error should happen, but got %v", err)
	}

	if err := DB.Where("id = $1", yasuo.ID).First(&Yasuo{}).Error; err != nil || yasuo.Name != "jinzhu" {
		t.Errorf("No error should happen, but got %v", err)
	}

	yasuo.Name = "jinzhu1"
	if err := DB.Save(&yasuo).Error; err != nil {

	}

	p4 := Product{Code: "after_save_error", Price: 100}
	DB.Save(&p4)
	if err := DB.First(&Product{}, "code = ?", "after_save_error").Error; err == nil {
		t.Fatalf("Record should be reverted if get an error in after save callback")
	}

	p5 := Product{Code: "after_delete_error", Price: 100}
	DB.Save(&p5)
	if err := DB.First(&Product{}, "code = ?", "after_delete_error").Error; err != nil {
		t.Fatalf("Record should be found")

http://127.0.0.1:8000/items/foo-item
```

... sem adicionar o parâmetro obrigatório `needy`, você verá um erro como:

```JSON
{
    "detail": [
        {
            "loc": [
                "query",
                "needy"
            ],
            "msg": "field required",
            "type": "value_error.missing"
        }
    ]
}
```

        if (isErrorEnabled()) {
            logger.error(toString(content));
        }
    }

    @Override
    public void error(CharSequence content, Throwable error) {
        if (isErrorEnabled()) {
            logger.error(toString(content), error);
        }
    }

    @Override
    public void error(Throwable error) {
        logger.error("", error);
    }

	SUBW	R7@>2, R5, R16                                   // ERROR "unsupported shift operator"
	SUBS	R7@>2, R5, R16                                   // ERROR "unsupported shift operator"
	SUBSW	R7@>2, R5, R16                                   // ERROR "unsupported shift operator"
	CMP	R7@>2, R5                                        // ERROR "unsupported shift operator"

	err = gob.NewDecoder(waitReader).Decode(&result)
	if err != nil {
		return result, err
	}
	if result.Error != "" {
		return result, errors.New(result.Error)
	}
	return result, nil
}

func (client *peerRESTClient) DriveSpeedTest(ctx context.Context, opts madmin.DriveSpeedTestOpts) (madmin.DriveSpeedTestResult, error) {
	queryVals := make(url.Values)
	if opts.Serial {
		queryVals.Set("serial", "true")
	}