$email = $_GET['email']; $cleaned_email = filter_var($email, FILTER_SANITIZE_EMAIL); if (filter_var($cleaned_email, FILTER_VALIDATE_EMAIL)) { // email is valid and can be used in the application } else { // email is invalid and should not be used in the application }In this example, the $_GET['email'] variable contains the user's email address as submitted through a form. The filter_var function is used with the FILTER_SANITIZE_EMAIL parameter to remove any unwanted characters from the email address. The function then checks whether the cleaned email address is valid using the FILTER_VALIDATE_EMAIL parameter, and performs appropriate actions based on the validity of the email address. The package library used in this example is the built-in PHP filter library, which provides a variety of functions for sanitizing and validating user input.