예를 들어 다음과 같은 `main.py` 파일이 있다고 합시다:

```Python hl_lines="3"
import os

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

/// tip | 팁

[`os.getenv()`](https://docs.python.org/3.8/library/os.html#os.getenv) 의 두 번째 인자는 반환할 기본값입니다.

제공하지 않으면 기본값은 `None`이며, 여기서는 사용할 기본값으로 `"World"`를 제공합니다.

///

그러면 해당 파이썬 프로그램을 다음과 같이 호출할 수 있습니다:

//// tab | Linux, macOS, Windows Bash

from fastapi import FastAPI
from fastapi.responses import JSONResponse

app = FastAPI()


@app.get("/headers/")
def get_headers():
    content = {"message": "Hello World"}
    headers = {"X-Cat-Dog": "alone in the world", "Content-Language": "en-US"}

	if count1 != count2 {
		t.Errorf("No user should not be deleted by invalid SQL")
	}
}

func TestSetAndGet(t *testing.T) {
	if value, ok := DB.Set("hello", "world").Get("hello"); !ok {
		t.Errorf("Should be able to get setting after set")
	} else if value.(string) != "world" {
		t.Errorf("Set value should not be changed")
	}

	if _, ok := DB.Get("non_existing"); ok {
		t.Errorf("Get non existing key should return error")
	}

router_b_a = APIRouter()
router_b_a_c_override = APIRouter()  # Overrides default class again


@app.get("/")
def get_root():
    return {"msg": "Hello World"}


@app.get("/override", response_class=PlainTextResponse)
def get_path_override():
    return "Hello World"


@router_a.get("/")
def get_a():
    return {"msg": "Hello A"}


@router_a.get("/override", response_class=PlainTextResponse)

from fastapi import FastAPI, Response

app = FastAPI()


@app.get("/headers-and-object/")
def get_headers(response: Response):
    response.headers["X-Cat-Dog"] = "alone in the world"

from fastapi import FastAPI

app = FastAPI()


@app.get("/app")
def read_main():
    return {"message": "Hello World from main app"}


subapi = FastAPI()


@subapi.get("/sub")
def read_sub():
    return {"message": "Hello World from sub API"}

from markupsafe import escape

flask_app = Flask(__name__)


@flask_app.route("/")
def flask_main():
    name = request.args.get("name", "World")
    return f"Hello, {escape(name)} from Flask!"


app = FastAPI()


@app.get("/v2")
def read_main():
    return {"message": "Hello World"}

# Code blocks { #code-blocks }

Some text

```python
# This is a sample Python code block
def hello_world():
    # Comment with indentation
    print("Hello, world!")  # Print greeting
```

Some more text

The following block is missing first line:

```toml
title = "TOML Example"  # Title of the document
```

And more text

```console
// Use the command "live" and pass the language code as a CLI argument

# Code blocks { #code-blocks }

Some text

```python
# This is a sample Python code block
def hello_world():
    # Comment with indentation
    print("Hello, world!")  # Print greeting
```

Some more text

```toml
# This is a sample TOML code block
title = "TOML Example"  # Title of the document
```

And more text

```console
// Use the command "live" and pass the language code as a CLI argument

        Did you *actually* encounter the need for this enhancement in a real-world scenario, or does
        it just seem like a sensible behavior for the feature to have?


        Before we make significant changes to existing features in Guava, we really want to be sure
        that it's for a use case that actually comes up in the real world. We want to hear the
        real-world use case so the community can discuss and debate whether this feature is actually