use Helper\Check; $username = Check::sanitizeString($_POST['username']); $email = Check::sanitizeEmail($_POST['email']); $password = Check::sanitizePassword($_POST['password']);This code sanitizes input data from a registration form, removing any special characters or HTML tags that could potentially cause security vulnerabilities. Package Library: It is difficult to determine the exact package library as "Helper check" is a very generic term that could refer to various PHP libraries. However, it could potentially refer to the "PHP Validation" package or the "PHP Input Validation" package, both of which provide similar functionality.