// v1-->v3
        graph.addEdge(v1, v3, new MetadataGraphEdge("1.1", true, null, null, 2, 1));
        graph.addEdge(v1, v3, new MetadataGraphEdge("1.2", true, null, null, 4, 2));

        // v3-->v4
        graph.addEdge(v3, v4, new MetadataGraphEdge("1.1", true, ArtifactScopeEnum.runtime, null, 2, 2));

        Map<String, Object> doc = new HashMap<>();

        assertEquals("default", DocumentUtil.getValue(doc, "nonexistent", String.class, "default"));
        assertEquals(Integer.valueOf(42), DocumentUtil.getValue(doc, "nonexistent", Integer.class, 42));
        assertEquals(Long.valueOf(123L), DocumentUtil.getValue(doc, "nonexistent", Long.class, 123L));

        doc.put("key", "value");

    assertEquals(null, Atomics.newReference(null).get());
    assertEquals(OBJECT, Atomics.newReference(OBJECT).get());
  }

  public void testNewReferenceArray_withLength() throws Exception {
    int length = 42;
    AtomicReferenceArray<String> refArray = Atomics.newReferenceArray(length);
    for (int i = 0; i < length; ++i) {
      assertEquals(null, refArray.get(i));
    }

  public void undirectedNetwork() {
    testNetworkMutation(NetworkBuilder.undirected());
  }

  private static void testNetworkMutation(NetworkBuilder<? super Integer, Object> networkBuilder) {
    Random gen = new Random(42); // Fixed seed so test results are deterministic.

    for (int trial = 0; trial < NUM_TRIALS; ++trial) {
      MutableNetwork<Integer, Object> network =

  }

  @Test
  public void undirectedGraph() {
    testGraphMutation(GraphBuilder.undirected());
  }

  private static void testGraphMutation(GraphBuilder<? super Integer> graphBuilder) {
    Random gen = new Random(42); // Fixed seed so test results are deterministic.

    for (int trial = 0; trial < NUM_TRIALS; ++trial) {
      MutableGraph<Integer> graph = graphBuilder.allowsSelfLoops(true).build();

  }

  @SuppressWarnings("ReturnValueIgnored")
  public void testMaximumWeight_withWeigher() {
    CacheBuilder<Object, Object> builder = CacheBuilder.from(parse("maximumWeight=9000"));
    builder.weigher(constantWeigher(42)).build(CacheLoader.from(Suppliers.ofInstance(null)));
  }

  @SuppressWarnings("ReturnValueIgnored")
  public void testMaximumWeight_withoutWeigher() {

      return 42;
    }

    @Override
    public boolean equals(@Nullable Object o) {
      return o instanceof SerializableTicker;
    }
  }

  private static class SerializableWeigher<K, V> implements Weigher<K, V>, Serializable {
    @Override
    public int weigh(K key, V value) {
      return 42;
    }

    @Override
    public int hashCode() {
      return 42;
    }

                + bin_to_hex(clock_seq_hi_and_reserved, 2) + bin_to_hex(clock_seq_low, 2) + '-' + bin_to_hex(node[0], 2)
                + bin_to_hex(node[1], 2) + bin_to_hex(node[2], 2) + bin_to_hex(node[3], 2) + bin_to_hex(node[4], 2)
                + bin_to_hex(node[5], 2);
    }

        }
    ]
}
```

경로 매개변수 `item_id`는 `int`가 아닌 `"foo"` 값이기 때문입니다.

`int`가 아닌 `float`을 전달하는 경우에도 동일한 오류가 나타납니다: <a href="http://127.0.0.1:8000/items/4.2" class="external-link" target="_blank">http://127.0.0.1:8000/items/4.2</a>

/// check | 확인

즉, 파이썬 타입 선언을 하면 **FastAPI**는 데이터 검증을 합니다.

오류에는 정확히 어느 지점에서 검증을 통과하지 못했는지 명시됩니다.

이는 API와 상호 작용하는 코드를 개발하고 디버깅하는 데 매우 유용합니다.

///

## 문서화

because the path parameter `item_id` had a value of `"foo"`, which is not an `int`.

The same error would appear if you provided a `float` instead of an `int`, as in: <a href="http://127.0.0.1:8000/items/4.2" class="external-link" target="_blank">http://127.0.0.1:8000/items/4.2</a>

/// check

So, with the same Python type declaration, **FastAPI** gives you data validation.