* @since 1.0.0-beta.27
	 *
	 * @return array
	 */
	public function get_item_schema_base() {

		$schema = parent::get_item_schema_base();

		// Section's title.
		$schema['properties']['title']['description'] = __( 'Section Title', 'lifterlms' );

		// Section's parent id.
		$schema['properties']['parent_id'] = array(
			'description' => __( 'WordPress post ID of the parent item. Must be a Course ID.', 'lifterlms' ),
			'type'        => 'integer',
			'context'     => array( 'view', 'edit' ),
			'arg_options' => array(
				'sanitize_callback' => 'absint',
			),
			'required'    => true,
		);

		// Section order.
		$schema['properties']['order'] = array(
			'description' => __( 'Order of the section within the course.', 'lifterlms' ),
			'type'        => 'integer',
			'default'     => 1,
			'context'     => array( 'view', 'edit' ),
			'arg_options' => array(
				'sanitize_callback' => 'absint',
			),
			'required'    => true,
		);

		// remove unnecessary properties.
		$unnecessary_properties = array(
			'permalink',
			'slug',
			'content',
			'menu_order',
			'excerpt',
			'featured_media',
			'status',
			'password',
			'featured_media',
			'comment_status',
			'ping_status',
		);

		foreach ( $unnecessary_properties as $unnecessary_property ) {
			unset( $schema['properties'][ $unnecessary_property ] );
		}