Inventory_Presser_Plugin::flush_rewrite( boolean $network_wide )

		public static function flush_rewrite( $network_wide ) {
			self::create_post_type();

			if ( ! is_multisite() || ! $network_wide ) {
				flush_rewrite_rules();
				return;
			}

			$sites = get_sites(
				array(
					'network' => 1,
					'limit'   => apply_filters( 'invp_query_limit', 1000, __METHOD__ ),
				)
			);
			foreach ( $sites as $site ) {
				switch_to_blog( $site->blog_id );
				global $wp_rewrite;
				$wp_rewrite->init(); // important...
				$wp_rewrite->flush_rules();
				restore_current_blog();
			}
		}