{!../../docs_src/python_types/tutorial009.py!}
```

`str` yerine `Optional[str]` kullanmak editorün bu değerin her zaman `str` tipinde değil bazen `None` tipinde de olabileceğini belirtir ve hataları tespit etmemizde yardımcı olur.

#### Generic tipler

Köşeli parantez içinde tip parametreleri alan bu türler, örneğin:

* `List`
* `Tuple`
* `Set`
* `Dict`
* `Optional`
* ...and others.

		cache.iamUsersMap = newCache.iamUsersMap
		// For STS policy map, we need to merge the new cache with the existing
		// cache because the periodic IAM reload is partial. The periodic load
		// here is to account for STS policy mapping changes that should apply
		// for service accounts derived from such STS accounts (i.e. LDAP STS
		// accounts).
		newCache.iamSTSPolicyMap.Range(func(k string, v MappedPolicy) bool {

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

O uso de `Optional[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`.

`Optional[Something]` é na verdade um atalho para `Union[Something, None]`, eles são equivalentes.

Isso também significa que no Python 3.10, você pode utilizar `Something | None`:

    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }

    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }

    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }

    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }

    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }

    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }

    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }