#### 字典 { #dict }

定义 `dict` 时，需要传入 2 个类型参数，用逗号分隔。

第一个类型参数用于字典的键。

第二个类型参数用于字典的值：

{* ../../docs_src/python_types/tutorial008_py310.py hl[1] *}

这表示：

* 变量 `prices` 是一个 `dict`：
    * 这个 `dict` 的键是 `str` 类型（比如，每个条目的名称）。
    * 这个 `dict` 的值是 `float` 类型（比如，每个条目的价格）。

#### Union { #union }

你可以声明一个变量可以是若干种类型中的任意一种，比如既可以是 `int` 也可以是 `str`。

        '^'.code,
        '`'.code,
        '{'.code,
        '|'.code,
        '}'.code,
      ).test(UrlComponentEncodingTester.Component.HOST)
  }

  @Test
  fun hostIpv6() {
    // Square braces are absent from host()...
    assertThat(parse("http://[::1]/").host).isEqualTo("::1")

    // ... but they're included in toString().
    assertThat(parse("http://[::1]/").toString()).isEqualTo("http://[::1]/")

        || (stimuli.length >= 5 && removes > 2)) {
      // removes are the most expensive thing to test, since they often throw exceptions with stack
      // traces, so we test them a bit less aggressively
      return;
    }

    MultiExceptionListIterator reference = new MultiExceptionListIterator(expectedElements);
    I target = newTargetIterator();

    /**
     * When potential deadlock is detected, this policy results in the throwing of the {@code
     * PotentialDeadlockException} indicating the potential deadlock, which includes stack traces
     * illustrating the cycle in lock acquisition order.
     */
    THROW {
      @Override
      public void handlePotentialDeadlock(PotentialDeadlockException e) {
        throw e;
      }
    },

Now, for FastAPI, it will see the return type and make sure that what you return includes **only** the fields that are declared in the type.

FastAPI does several things internally with Pydantic to make sure that those same rules of class inheritance are not used for the returned data filtering, otherwise you could end up returning much more data than what you expected.

import org.codelibs.fess.util.ComponentUtil;
import org.dbflute.optional.OptionalEntity;

/**
 * Manages a dictionary file for synonyms.
 * This class handles reading, parsing, and updating files that contain
 * synonym rules. The file format supports both explicit mappings (e.g., `a => b`)
 * and equivalent synonyms (e.g., `a, b, c`).
 *
 * The class provides methods for retrieving, adding, updating, and

import org.jspecify.annotations.Nullable;

/**
 * Statistics about the performance of a {@link Cache}. Instances of this class are immutable.
 *
 * <p>Cache statistics are incremented according to the following rules:
 *
 * <ul>
 *   <li>When a cache lookup encounters an existing cache entry {@code hitCount} is incremented.
 *   <li>When a cache lookup first encounters a missing cache entry, a new entry is loaded.
 *       <ul>

import org.jspecify.annotations.Nullable;

/**
 * Statistics about the performance of a {@link Cache}. Instances of this class are immutable.
 *
 * <p>Cache statistics are incremented according to the following rules:
 *
 * <ul>
 *   <li>When a cache lookup encounters an existing cache entry {@code hitCount} is incremented.
 *   <li>When a cache lookup first encounters a missing cache entry, a new entry is loaded.
 *       <ul>

    data = some_blocking_library.fetch_items()
    return data
```

In case of doubt, or by default, use regular `def` functions, those will be run in a threadpool so they don't block the event loop.

The same rules apply to dependencies.

Make sure blocking code is not run inside of `async` functions. The logic will work, but will damage the performance heavily.

`dict`를 정의하려면, 쉼표로 구분된 2개의 타입 매개변수를 전달합니다.

첫 번째 타입 매개변수는 `dict`의 키를 위한 것입니다.

두 번째 타입 매개변수는 `dict`의 값을 위한 것입니다:

{* ../../docs_src/python_types/tutorial008_py310.py hl[1] *}

이는 다음을 의미합니다:

* 변수 `prices`는 `dict`입니다:
    * 이 `dict`의 키는 `str` 타입입니다(예: 각 아이템의 이름).
    * 이 `dict`의 값은 `float` 타입입니다(예: 각 아이템의 가격).

#### Union { #union }

변수가 **여러 타입 중 어떤 것이든** 될 수 있다고 선언할 수 있습니다. 예를 들어 `int` 또는 `str`입니다.