PhpCsFixer\Fixer\Casing\LowercaseKeywordsFixer::fix PHP Method

    public function fix(\SplFileInfo $file, Tokens $tokens)
    {
        foreach ($tokens as $token) {
            if ($token->isKeyword() && !$token->isGivenKind(self::$excludedTokens)) {
                $token->setContent(strtolower($token->getContent()));
            }
        }
    }