I ran phpcs and got the following error:
[x] Arithmetic operation must be bracketed

So I ran phpcbf to auto-fix it, and it changed the code line from:
$results = $stmt->fetchAll(\PDO::FETCH_ASSOC | \PDO::FETCH_GROUP | \PDO::FETCH_UNIQUE);

to a syntax error:
$results = $stmt->fetchAll(\(PDO::FETCH_ASSOC | ) \(PDO::FETCH_GROUP | ) \PDO::FETCH_UNIQUE);