WordPress Cron running in a php class on a custom schedule

class-cron-pull.php

<?php namespace MyProject;
/**
 * Cron Pull
 *
 * Cron functionality for pulling data on a regular basis
 *
 * @package MyProject
 */
use WP_Query;

class Cron_Pull {
	/**
	 * Holds the singleton instance.
	 *
	 * @static
	 * @var object
	 */
	private static $_instance = null;

	/**
	 * The cron action hook we will be using.
	 *
	 * @var string
	 */
	private $_cron_hook = 'myproject_pull';

	/**
	 * Get a reference to the singleton.
	 *
	 * @return object The singleton instance.
	 */
	public static function instance() {
		if ( ! isset( self::$_instance ) ) {
			self::$_instance = new self();
		}
		return self::$_instance;
	}

	/**
	 * Cron_Pull constructor.
	 */
	public function __construct() {
		register_deactivation_hook( MYPROJECT_PULL_PLUGIN_FILE, [ $this, 'deactivated' ] );

	}

	/**
	 * Initialize this class when the plugin loads.
	 */
	public function init() {

		add_action( $this->_cron_hook, [ $this, 'run_cron' ] );
		add_filter( 'cron_schedules', [ $this, 'cron_intervals' ] );

		if ( ! wp_next_scheduled( $this->_cron_hook ) ) {
			wp_schedule_event( time(), 'myproject_custom_schedule', $this->_cron_hook );
		}
	}

	/**
	 * Filter the cron_intervals to add our custom schedule to the existing ones.
	 *
	 * @param array $schedules The existing cron schedules.
	 * @return mixed Send back the array of all cron schedules.
	 */
	public function cron_intervals( $schedules ) {

		$schedules['myproject_custom_schedule'] = [
			'interval' => intval( MYPROJECT_PULL_CRON_SCHEDULE_DAYS ) * DAY_IN_SECONDS,
			'display' => 'Every ' . MYPROJECT_PULL_CRON_SCHEDULE_DAYS . ' days',
		];

		return $schedules;
	}

	/**
	 * Main functionality of this class, running the cron function.
	 */
	public function run_cron() {

		// TODO: Do the stuff here!

	}



	/**
	 * When the plugin deactivates we want to unschedule our cron event.
	 */
	public function deactivated() {
		wp_unschedule_event( wp_next_scheduled( $this->_cron_hook ), $this->_cron_hook );
	}

}
define( 'MYPROJECT_PULL_PLUGIN_FILE', __FILE__ );
define( 'MYPROJECT_PULL_CRON_SCHEDULE_DAYS',14)
add_action( 'plugins_loaded', [ Cron_Pull::instance(), 'init' ] );