.collect(Collectors.toSet());
    }

    private ClassRealm newRealm(String id) {
        synchronized (world) {
            String realmId = id;

            Random random = new Random();

            while (true) {
                try {
                    ClassRealm classRealm = world.newRealm(realmId, null);

                    logger.debug("Created new class realm {}", realmId);

      placeholder: |
        from fastapi import FastAPI

        app = FastAPI()


        @app.get("/")
        def read_root():
            return {"Hello": "World"}
      render: python
    validations:
      required: true
  - type: textarea
    id: description
    attributes:
      label: Description
      description: |
        What is the problem, question, or error?

🖼 👆 💪 ✔️ 📁 `main.py` ⏮️:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

/// tip

🥈 ❌ <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> 🔢 💲 📨.

🚥 🚫 🚚, ⚫️ `None` 🔢, 📥 👥 🚚 `"World"` 🔢 💲 ⚙️.

///

⤴️ 👆 💪 🤙 👈 🐍 📋:

<div class="termy">

```console

from fastapi.middleware.httpsredirect import HTTPSRedirectMiddleware

app = FastAPI()

app.add_middleware(HTTPSRedirectMiddleware)


@app.get("/")
async def main():

from typing import Union


def say_hi(name: Union[str, None] = None):
    if name is not None:
        print(f"Hey {name}!")
    else:

      description: |
        How has this issue affected you? What are you trying to accomplish? What other alternatives have you considered?
        Providing context helps us come up with a solution that is most useful in the real world
    validations:

      label: Context (optional)
      description: |
        How has this issue affected you? What are you trying to accomplish?
        Providing context helps us come up with a solution that is most useful in the real world
    validations:
      required: false
  - type: input
    id: page
    attributes:
      label: Page with the problem
      description: Please, provide a link to the relevant documentation page
    validations:

import uvicorn
from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def root():
    a = "a"
    b = "b" + a
    return {"hello world": b}


if __name__ == "__main__":

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

wäre die Response etwa:

```JSON
{
    "message": "Hello World",
    "root_path": "/api/v1"
}
```

### Festlegen des `root_path` in der FastAPI-Anwendung

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

返回的响应如下：

```JSON
{
    "message": "Hello World",
    "root_path": "/api/v1"
}
```

### 在 FastAPI 应用里设置 `root_path`

还有一种方案，如果不能提供 `--root-path` 或等效的命令行选项，则在创建 FastAPI 应用时要设置 `root_path` 参数。

```Python hl_lines="3"