I introduced black to vscode, but it doesn't autoformat

Introduction

Black that doesn't work at all. Why is that?

Checkpoint

1. Is python 3.6 or later?
2. Are you making the appropriate settings?
3. Is the option attached incorrectly?

I was addicted to number 3. After all it is not good to change various things suddenly ...

settings.json

    "[python]": {
        "editor.tabSize": 4,
        "editor.detectIndentation": false,
        "editor.formatOnSave": true,
    },
    "python.linting.enabled":true,
    "python.linting.pylintEnabled": false,
    "python.linting.flake8Enabled": true,
    "python.linting.lintOnSave":true,
    "python.formatting.provider": "black",
    "python.linting.flake8Args": [
        "--max-line-length=120",
        "--ignore=E203,W503,W504"
      ],
    "python.formatting.blackArgs": [
        "--line-length=120"
      ],

The problem with automatic formatting not working was how to specify the maximum number of characters per line.

• flake8→ max-line-length
• black → line-length seriously that's all.