remove(group_key, group_id, data, modifiers, callback) {
        const identifiers = {$group_key: group_key, $group_id: group_id};
        this._remove({identifiers, data, modifiers, callback});
    }
groups.remove(group_key, group_id, data, modifiers, callback)
        ---
        remove a value from a list-valued group profile property.

        usage:

        mixpanel.groups.remove('company', 'Acme Inc.', {'products': 'anvil'});

        mixpanel.groups.remove('company', 'Acme Inc.', {
            'products': 'anvil',
            'customer segments': 'coyotes'
        });