Composer installed Php-cs-fixer, using--level error

Through php-cs-fixer fix path/ --level=psr2 This command will report the following error, without adding will --level not error, but the official website has this parameter

Version:
Ubuntu 16.04 LTS
PHP CS Fixer version 2.0-dev by Fabien Potencier and Dariusz Ruminski

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Through php-cs-fixer fix path/ --level=psr2 This command will report the following error, without adding will --level not error, but the official website has this parameter

Version:
Ubuntu 16.04 LTS
PHP CS Fixer version 2.0-dev by Fabien Potencier and Dariusz Ruminski

You see where the document, is not the version of the same
Https://github.com/FriendsOfPHP/PHP-CS-Fixer
This parameter is not found here either.
I didn't use this stuff, so it's not clear that laxatives

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