// vol. 2, Knuth, 4.2.2, (16) to the two-variable case. We have two value series x_i and y_i.
    // We define the arithmetic means X_n = 1/n \sum_{i=1}^n x_i, and Y_n = 1/n \sum_{i=1}^n y_i.
    // We also define the sum of the products of the differences from the means
    //           C_n = \sum_{i=1}^n x_i y_i - n X_n Y_n
    // for all n >= 1. Then for all n > 1:

        assertEquals(0, offsetBuffer.length);
    }

    @Test
    void testDerive() {
        ndrBuffer.advance(50); // Advance the original buffer
        NdrBuffer derivedBuffer = ndrBuffer.derive(10);

        // Verify derived buffer properties
        assertSame(buffer, derivedBuffer.buf);
        assertEquals(0, derivedBuffer.start); // Derived buffer starts from the original buffer's start

### Short { #short }

It has sensible **defaults** for everything, with optional configurations everywhere. All the parameters can be fine-tuned to do what you need and to define the API you need.

But by default, it all **"just works"**.

### Validation { #validation }

* Validation for most (or all?) Python **data types**, including:
    * JSON objects (`dict`).

 * This service provides functionality to create, read, update, and delete
 * duplicate host configurations used by the Fess crawler system.
 *
 * <p>Duplicate host configurations allow administrators to define hostname patterns
 * that should be treated as equivalent during crawling. This helps avoid indexing
 * duplicate content from the same logical site that may be accessible via different

* `DELETE`: удалить данные.

Таким образом, в OpenAPI каждый HTTP-метод называется «операцией».

Мы тоже будем называть их «операциями».

#### Определите *декоратор операции пути (path operation decorator)* { #define-a-path-operation-decorator }

{* ../../docs_src/first_steps/tutorial001_py310.py hl[6] *}

`@app.get("/")` сообщает **FastAPI**, что функция прямо под ним отвечает за обработку запросов, поступающих:

* по пути `/`

* `POST`: 데이터를 생성하기 위해.
* `GET`: 데이터를 읽기 위해.
* `PUT`: 데이터를 수정하기 위해.
* `DELETE`: 데이터를 삭제하기 위해.

그래서 OpenAPI에서는 각 HTTP 메소드들을 "작동"이라 부릅니다.

우리 역시 이제부터 메소드를 "**작동**"이라고 부를 것입니다.

#### *경로 처리 데코레이터* 정의 { #define-a-path-operation-decorator }

{* ../../docs_src/first_steps/tutorial001_py310.py hl[6] *}

`@app.get("/")`은 **FastAPI**에게 바로 아래에 있는 함수가 다음으로 이동하는 요청을 처리한다는 것을 알려줍니다:

* 경로 `/`

        self.scheme_name = scheme_name or self.__class__.__name__
        self.auto_error = auto_error

    def make_not_authenticated_error(self) -> HTTPException:
        """
        The OAuth 2 specification doesn't define the challenge that should be used,
        because a `Bearer` token is not really the only option to authenticate.

        But declaring any other authentication challenge would be application-specific

```
KEY:
storage_class  define object level redundancy

ARGS:
standard  (string)    set the parity count for default standard storage class e.g. "EC:4"
rrs       (string)    set the parity count for reduced redundancy storage class e.g. "EC:2"
comment   (sentence)  optionally add a comment to this setting
```

or environment variables

```
KEY:
storage_class  define object level redundancy

ARGS:

      return emptySet();
    }
  }

  /**
   * Creates a suite whose map has some elements filtered out of view.
   *
   * <p>Because the map may be ascending or descending, this test must derive the relative order of
   * these extreme values rather than relying on their regular sort ordering.
   */
  final TestSuite createSubmapSuite(
      FeatureSpecificTestSuiteBuilder<

It will perform the validation of the compound data, and will document it like that for the OpenAPI schema and automatic docs.

## Singular values in body { #singular-values-in-body }

The same way there is a `Query` and `Path` to define extra data for query and path parameters, **FastAPI** provides an equivalent `Body`.