Crtitacal WooCommerce error

Dear Support,

I found this critical error in my WooCommerce logs from yesterday, can you please help understand it and fix it?

2019-09-01T16:31:32+00:00 CRITICAL Call to a member function get_cart() on null u /nfs/c10/h10/mnt/226537/domains/prirodna.com/html/v2/wp-content/plugins/physc-builder/inc/functions.php on line 234

Thanks and best regards,

Dubravko