restricted mail from Wordpress

copy this code and past functions.php page.
/**
     * @author Bashar
     * @param WP_Error $errors
     * @param string $sanitized_user_login
     * @param string $user_email
     * @return WP_Error $errors
     */
    function mh_check_email_provider($errors, $sanitized_user_login, $user_email){
        // Allowed Email provider. Must include extention
        $allowed_provider = array('yahoo.com', 'gmail.com', 'ymail.com', 'live.com', 'msn.com');

        // Get users email provider
        $user_mail_provider = substr($user_email, strpos($user_email, '@')+1);
        // Check if users email provider is allowed
        if(in_array($user_mail_provider, $allowed_provider)){
            // Allowed provider:)
            // Return unchanged $erorrs
            return $errors;
        }
        // Provider not allowed :(
        // Add error code and return
        $errors->add( 'restricted_emial_provider', __( '<strong>ERROR</strong>: We only support ' . implode(', ', $allowed_provider) ) );
        return $errors;
        // That's it
    }
    add_filter('registration_errors', 'mh_check_email_provider', 100, 3);