public function initialize_session() {
		// Session class, handles session data for users - can be overwritten if custom handler is needed.
		$session_class = apply_filters( 'woocommerce_session_handler', 'WC_Session_Handler' );
		if ( is_null( $this->session ) || ! $this->session instanceof $session_class ) {
			$this->session = new $session_class();
			$this->session->init();
		}
	}