WordPress plugin Sanitise and Validate settinhgs fields

WordPress plugin Sanitise and Validate settinhgs fields.php

<?php

// In the main plugin file:

/* Register settings */
function my_cool_plugin_settings_init() {
    register_setting (
	'my_cool_plugin_settings',
	'my_cool_plugin_settings',
    'my_cool_plugin_settings_validate'
	);
}
add_action( 'admin_init', 'my_cool_plugin_settings_init' );


/* Sanitize and validate */
function my_cool_plugin_settings_validate( $input ) {
    $output = array();
    foreach ( $input as $key => $value ) {
        if ( isset( $input[$key] ) ) {
            if ( is_array( $input[$key] ) ) {
                $output[$key] = array_map( 'sanitize_text_field', $input[$key] );
            } else {
                /* Preserve line breaks while stripping HTML tags */
                $output[$key] = wp_kses( $input[$key], array( 'br' => array() ) );
            }
        }
    }
    return $output;
    wp_verify_nonce($_POST['my-cool-plugin-settings'], 'save-my-cool-plugin-settings');
}


// The settings page form

<form method="post" action="options.php">

    // All fields here....

    <?php wp_nonce_field( 'save-my-cool-plugin-settings','my-cool-plugin-settings' ) ?>
</form>