code: def <<(item)
        fetch
  
        if item.is_a?(Resource)
          if item.is_a?(@resource_class)
            @resources << item
          else
            raise "this collection is for #{@resource_class}"
          end
        else
          @resources << wrap_resource(item, true)
        end
      end
docs: Adds an item to this collection
   @option item [ZendeskAPI::Data] the resource to add
   @raise [ArgumentError] if the resource doesn't belong in this collection