```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`

     * The error's stacktrace will be output when this error level is enabled.
     *
     * @param content
     * @param error
     */
    void error(CharSequence content, Throwable error);

    /**
     * Send an exception to the user in the <b>error</b> error level.<br>
     * The stack trace for this exception will be output when this error level is enabled.
     *
     * @param error

		}
	}

	// Failed to identify what type of error this, return a simple UI error
	return Err{msg: err.Error()}
}

// FmtError converts a fatal error message to a more clear error
// using some colors
func FmtError(introMsg string, err error, jsonFlag bool) string {
	renderedTxt := ""
	uiErr := ErrorToErr(err)
	// JSON print
	if jsonFlag {

	ipsetIPHashCreate(name string, v6 bool) error
	destroySet(name string) error
	addIP(name string, ip netip.Addr, ipProto uint8, comment string, replace bool) error
	deleteIP(name string, ip netip.Addr, ipProto uint8) error
	flush(name string) error
	clearEntriesWithComment(name string, comment string) error
	clearEntriesWithIP(name string, ip netip.Addr) error
	listEntriesByIP(name string) ([]netip.Addr, error)
}

    assertThat(oneValueAccumulator.mean()).isWithin(ALLOWED_ERROR).of(ONE_VALUE);
    assertThat(oneValueAccumulatorByAddAllEmptyStats.mean()).isWithin(ALLOWED_ERROR).of(ONE_VALUE);
    assertThat(twoValuesAccumulator.mean()).isWithin(ALLOWED_ERROR).of(TWO_VALUES_MEAN);
    assertThat(twoValuesAccumulatorByAddAllStats.mean())
        .isWithin(ALLOWED_ERROR)
        .of(TWO_VALUES_MEAN);

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

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

    @Override
    public boolean isDebugEnabled() {
        return logger.isDebugEnabled();
    }

    @Override

	}

	if tx.Error != nil {
		t.Errorf("Should not raise any error, but got %v", tx.Error)
	}

	AssertObjEqual(t, result, data, "Name", "Gender", "Age")

	if err := DB.Where(data).Assign(ScannerValuerStruct{Age: sql.NullInt64{Int64: 18, Valid: true}}).FirstOrCreate(&result).Error; err != nil {
		t.Errorf("Should not raise any error, but got %v", err)
	}

	if result.Age.Int64 != 18 {

            }
            for (Map.Entry<File, List<Error>> e : errors.entrySet()) {
                File file = e.getKey();
                List<Error> errorsForFile = e.getValue();

                StringBuilder sb = new StringBuilder();
                for (Error error : errorsForFile) {
                    sb.append("ERROR: " + file.getName() + ":" + error.lineNumber + " " + error.message + "\n    " + error.line + "\n");
                }

			if tc.error == "" && err != nil {
				t.Fatalf("expected no error, got %v", err)
			}
			if tc.error != "" {
				if err == nil {
					t.Fatalf("expected error to include \"%s\" but got none", tc.error)
				}
				if !strings.Contains(err.Error(), tc.error) {
					t.Fatalf("expected \"%s\" in error, got %v", tc.error, err)
				}
			}
		})
	}

	}

	if err := tx.Commit().Error; err != nil {
		t.Errorf("Failed to commit transaction, got error %v\n", err)
	}

	if result := db.Where("name=?", "zzjin").Delete(&User{}); result.Error != nil || result.RowsAffected != 1 {
		t.Fatalf("Failed, got error: %v, rows affected: %v", result.Error, result.RowsAffected)
	}

	tx2 := db.Begin()