Limit event to one for nested lists

[ap-prog]

With this code on nested lists

let options = {
    group: {
        name : 'items'
    },
    onSort: function() {
      console.log('sorted');
    }
};

Sortable.create(document.getElementById('items'), options);
Sortable.create(document.getElementById('items-1'), options);
Sortable.create(document.getElementById('items-2'), options);

Moving an item from within a nested list into the parent list triggers the onSort event twice (I guess, once for the nested list and once for the parent list). I'm using the onSort event to call other functions and getting two events almost simultaneously is causing issues.

Is there way to get only one event when sorting has completed?