return CollectCollectors.flatteningToImmutableListMultimap(keyFunction, valuesFunction);
  }

  /**
   * Returns the empty multimap.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  // Casting is safe because the multimap will never hold any elements.
  @SuppressWarnings("unchecked")
  public static <K, V> ImmutableListMultimap<K, V> of() {

Auf diese Weise müssen Sie Ihre lokale Version nicht „installieren“, um jede Änderung testen zu können.

/// note | "Technische Details"

Das geschieht nur, wenn Sie die Installation mit der enthaltenen `requirements.txt` durchführen, anstatt `pip install fastapi` direkt auszuführen.

```

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="17  22  24-27"
{!> ../../docs_src/response_model/tutorial001_py310.py!}
```

////

/// note

👀 👈 `response_model` 🔢 "👨‍🎨" 👩‍🔬 (`get`, `post`, ♒️). 🚫 👆 *➡ 🛠️ 🔢*, 💖 🌐 🔢 & 💪.

///

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

          .isEqualTo(!(Double.isNaN(value) || Double.isInfinite(value)));
    }
  }

  public void testCompare() {
    for (double x : VALUES) {
      for (double y : VALUES) {
        // note: spec requires only that the sign is the same
        assertWithMessage(x + ", " + y)
            .that(Doubles.compare(x, y))
            .isEqualTo(Double.valueOf(x).compareTo(y));
      }
    }
  }

    }
    return (char) value;
  }

  /**
   * Compares the two specified {@code char} values. The sign of the value returned is the same as
   * that of {@code ((Character) a).compareTo(b)}.
   *
   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated; use the
   * equivalent {@link Character#compare} method instead.
   *
   * @param a the first {@code char} to compare

    }
    return (short) value;
  }

  /**
   * Compares the two specified {@code short} values. The sign of the value returned is the same as
   * that of {@code ((Short) a).compareTo(b)}.
   *
   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated; use the
   * equivalent {@link Short#compare} method instead.
   *
   * @param a the first {@code short} to compare

    putAll(multimap);
  }

  /**
   * Adds a new node for the specified key-value pair before the specified {@code nextSibling}
   * element, or at the end of the list if {@code nextSibling} is null. Note: if {@code nextSibling}
   * is specified, it MUST be for a node for the same {@code key}!
   */
  @CanIgnoreReturnValue
  private Node<K, V> addNode(
      @ParametricNullness K key,

    }
    return (short) value;
  }

  /**
   * Compares the two specified {@code short} values. The sign of the value returned is the same as
   * that of {@code ((Short) a).compareTo(b)}.
   *
   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated; use the
   * equivalent {@link Short#compare} method instead.
   *
   * @param a the first {@code short} to compare

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


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

**Note**:

如果你不知道是否会用到，可以查看文档的 _"In a hurry?"_ 章节中 <a href="https://fastapi.tiangolo.com/zh/async/#in-a-hurry" target="_blank">关于 `async` 和 `await` 的部分</a>。

</details>

### 运行

通过以下命令运行服务器：