예를 들어, 어떤 값이 `str` 또는 `None`이 될 수 있다고 선언할 수 있습니다:

```python
from typing import Union


def say_hi(name: Union[str, None]):
        print(f"Hi {name}!")
```

`typing`에는 `None`이 될 수 있음을 선언하는 축약형으로 `Optional`도 있습니다.

아주 개인적인 관점에서의 팁입니다:

- 🚨 `Optional[SomeType]` 사용은 피하세요
- 대신 ✨ **`Union[SomeType, None]`를 사용하세요** ✨.

	for i := range 5 {
		items = append(items, TestItem{
			Name:     fmt.Sprintf("test-item-%d", i),
			Property: "property",
		})
	}
	if _, err := store.PutMultiple(items); err != nil {
		t.Fatalf("failed to put multiple; %v", err)
	}

	for i := 5; i < 10; i++ {
		item := TestItem{
			Name:     fmt.Sprintf("test-item-%d", i),
			Property: "property",
		}

# 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 has wrong language code (should be TOML):

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

And more text

```console

		Can be repeated to define multiple symbols.
	-I dir1 -I dir2
		Search for #include files in dir1, dir2, etc,
		after consulting $GOROOT/pkg/$GOOS_$GOARCH.
	-S
		Print assembly and machine code.
	-V
		Print assembler version and exit.
	-debug
		Dump instructions as they are parsed.
	-dynlink
		Support references to Go symbols defined in other shared libraries.
	-e

# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.

# Run go tool dist to install a command.
# The -v causes dist to print the name of each directory as it runs.
# The -vv causes dist to print each build command as it runs.
# go tool dist clean cleans all directories, not just this one,
# but it's as close as we can get.

# Default target (first).
install:

# 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

# 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
```

Extra code block

```
$ cd my_project
```

And more text

```console

	plainMsg := "You are running an older version of MinIO released"

	for i, testCase := range testCases {
		output := prepareUpdateMessage(testCase.dlURL, testCase.older)
		line1 := fmt.Sprintf("%s %s", plainMsg, color.YellowBold(testCase.expectedSubStr))
		line2 := fmt.Sprintf("Update: %s", color.CyanBold(testCase.dlURL))
		// Uncomment below to see message appearance:
		// fmt.Println(output)
		switch {
		case testCase.dlURL == "" && output != "":

		m := MSS(typed)
		trace.Path += m.ToQuery()
	case *URLValues:
		trace.Path += typed.Values().Encode()
	case *NoPayload, *Bytes:
		trace.Path = fmt.Sprintf("%s?payload=%T", trace.Path, typed)
	case string:
		trace.Path = fmt.Sprintf("%s?%s", trace.Path, typed)
	default:
	}
	trace.HTTP.ReqInfo.Path = trace.Path

	t.Publisher.Publish(trace)
	return resp, err

			if n != 10000 {
				panic(fmt.Sprintf("wlock(%d)\n", n))
			}
			for range 100 {
			}
			atomic.AddInt32(activity, -10000)
			rwm.Unlock(context.Background())
		}
	}
	cdone <- true
}

// Borrowed from rwmutex_test.go
func hammerRWMutex(t *testing.T, gomaxprocs, numReaders, numIterations int) {
	t.Run(fmt.Sprintf("%d-%d-%d", gomaxprocs, numReaders, numIterations), func(t *testing.T) {