We annotate the function return type as `BaseUser`, but we are actually returning a `UserIn` instance.

The editor, mypy, and other tools won't complain about this because, in typing terms, `UserIn` is a subclass of `BaseUser`, which means it's a *valid* type when what is expected is anything that is a `BaseUser`.

    assertThrows(IndexOutOfBoundsException.class, () -> iia3.subArray(1, 4));
  }

  /*
   * Whenever an implementation uses `instanceof` on a parameter instance, the test has to know that
   * (so much for "black box") and try instances that both do and don't pass the check. The "don't"
   * half of that is more awkward to arrange...
   */

Sie können alle [Starlette](https://www.starlette.dev/)-Funktionalitäten auch mit `FastAPI` nutzen.

///

### Schritt 2: Erzeugen einer `FastAPI`-„Instanz“ { #step-2-create-a-fastapi-instance }

{* ../../docs_src/first_steps/tutorial001_py310.py hl[3] *}

In diesem Beispiel ist die Variable `app` eine „Instanz“ der Klasse `FastAPI`.

  static final String ERROR_SELF_LOOP = "self-loops are not allowed";
  static final String ERROR_ADDED_SELF_LOOP = "Should not be allowed to add a self-loop edge.";

  /** Creates and returns an instance of the graph to be tested. */
  abstract Graph<Integer> createGraph();

  /**
   * A proxy method that adds the node {@code n} to the graph being tested. In case of Immutable

	startTime            time.Time // Start time for window
	expMovingAvg         float64   // Previously calculated exponential moving average
}

// newRateMeasurement creates a new instance of the measurement with the initial start time.
func newRateMeasurement(initTime time.Time) *rateMeasurement {
	return &rateMeasurement{
		startTime: initTime,
	}
}

/// note | 技術細節

`FastAPI` 是一個直接繼承自 `Starlette` 的類別。

你同樣可以透過 `FastAPI` 來使用 [Starlette](https://www.starlette.dev/) 所有的功能。

///

### 第二步：建立一個 `FastAPI`「實例」 { #step-2-create-a-fastapi-instance }

{* ../../docs_src/first_steps/tutorial001_py310.py hl[3] *}

這裡的 `app` 變數將會是 `FastAPI` 類別的「實例」。

這將是你建立所有 API 的主要互動點。

### 第三步：建立一個「路徑操作」 { #step-3-create-a-path-operation }

        assertEquals(strictlyOrderedList, ordering.immutableSortedCopy(nonNullShuffledList));
      }
    }
  }

  /**
   * A means for changing an Ordering into another Ordering. Each instance is responsible for
   * creating the alternate Ordering, and providing a List that is known to be ordered, based on an
   * input List known to be ordered according to the input Ordering.
   */

        assertEquals(strictlyOrderedList, ordering.immutableSortedCopy(nonNullShuffledList));
      }
    }
  }

  /**
   * A means for changing an Ordering into another Ordering. Each instance is responsible for
   * creating the alternate Ordering, and providing a List that is known to be ordered, based on an
   * input List known to be ordered according to the input Ordering.
   */

     */
    public static class PathInfo {
        private final String path;
        private final String name;

        /**
         * Creates a new PathInfo instance.
         *
         * @param path the directory path component
         * @param name the file or directory name component
         */
        public PathInfo(final String path, final String name) {

Você pode usar todas as funcionalidades do [Starlette](https://www.starlette.dev/) com `FastAPI` também.

///

### Passo 2: crie uma "instância" de `FastAPI` { #step-2-create-a-fastapi-instance }

{* ../../docs_src/first_steps/tutorial001_py310.py hl[3] *}

Aqui, a variável `app` será uma "instância" da classe `FastAPI`.

Este será o principal ponto de interação para criar toda a sua API.