## 선택적 매개변수

같은 방법으로 기본값을 `None`으로 설정하여 선택적 매개변수를 선언할 수 있습니다:

{* ../../docs_src/query_params/tutorial002.py hl[9] *}

이 경우 함수 매개변수 `q`는 선택적이며 기본값으로 `None` 값이 됩니다.

/// check | 확인

**FastAPI**는 `item_id`가 경로 매개변수이고 `q`는 경로 매개변수가 아닌 쿼리 매개변수라는 것을 알 정도로 충분히 똑똑합니다.

///

/// note | 참고

FastAPI는 `q`가 `= None`이므로 선택적이라는 것을 인지합니다.

* Change eviction logic in NodeController and make it Zone-aware ([#28897](https://github.com/kubernetes/kubernetes/pull/28897), [@gmarek](https://github.com/gmarek))
    * Change eviction policies in NodeController:
      *  add a "partialDisruption" mode, when more than 33% of Nodes in the zone are not Ready
      *  add "fullDisruption" mode, when all Nodes in the zone are not Ready

```Python
q: Union[str, None] = None
```

Ou como em Python 3.10 e versões superiores:

```Python
q: str | None = None
```

Por exemplo:

{* ../../docs_src/body_multiple_params/tutorial004_py310.py hl[26] *}

/// info | Informação

    /**
     * SAX event handler called when an XML start element is encountered.
     * Processes collection definitions and tracks the element hierarchy.
     *
     * @param uri the namespace URI, or empty string if none
     * @param localName the local name without prefix, or empty string if namespace processing is not performed
     * @param qName the qualified name with prefix, or empty string if qualified names are not available

	h.ItemsSkipped = h.ResumeItemsSkipped
	h.BytesDone = h.ResumeBytesDone
	h.BytesFailed = h.ResumeBytesFailed
	h.BytesSkipped = h.ResumeBytesSkipped
}

// bucketDone should be called when a bucket is done healing.
// Adds the bucket to the list of healed buckets and updates resume numbers.
func (h *healingTracker) bucketDone(bucket string) {
	h.mu.Lock()
	defer h.mu.Unlock()

	h.ResumeItemsHealed = h.ItemsHealed

      // When a listener is first added, we run a task that will wait for the delegate to finish,
      // and when it is done will run the listeners.
      if (hasListeners.compareAndSet(false, true)) {
        if (delegate.isDone()) {
          // If the delegate is already done, run the execution list immediately on the current
          // thread.
          executionList.execute();
          return;
        }

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

 *  Fix: Change HTTP/2 to use a daemon thread for its socket reader. If you've ever seen a command
    line application hang after all of the work is done, it may be due to a non-daemon thread like
    this one.
 *  New: Include suppressed exceptions when all routes to a target service fail.


## Version 4.4.1

_2020-03-08_

    assertMapEquals(ImmutableSortedMap.of("one", 1), "one", 1);
    assertMapEquals(ImmutableSortedMap.of("one", 1, "two", 2), "one", 1, "two", 2);
    assertMapEquals(
        ImmutableSortedMap.of("one", 1, "two", 2, "three", 3), "one", 1, "three", 3, "two", 2);
    assertMapEquals(
        ImmutableSortedMap.of("one", 1, "two", 2, "three", 3, "four", 4),
        "four",
        4,
        "one",
        1,
        "three",

        .expectCollects(
            new ImmutableTable.Builder<String, String, Integer>()
                .put("one", "uno", 1)
                .put("two", "dos", 2)
                .put("three", "tres", 3)
                .buildOrThrow(),
            immutableCell("one", "uno", 1),
            immutableCell("two", "dos", 2),
            immutableCell("three", "tres", 3));
  }