code: def remove!(*items)
        return false unless @delegate.respond_to?(:op_remove_relation!)
        items = items.flatten.parse_pointers
        @delegate.send :op_remove_relation!, @key, items
      end
docs: Atomically remove a set of Parse::Objects to this relation.
   This is done by making the API request directly with Parse server; the
   local object is not updated with changes.