    # File lib/fog/cloudstack/models/compute/volume.rb, line 81
            def attach(instance_or_id, mountpoint=nil)
              requires :id
              instance_id = instance_or_id.is_a?(Server) ? instance_or_id.id : instance_or_id
              unless instance_id
                raise ArgumentError, "Missing required argument: instance_or_id"
              end

              options = {
                'id'               => id,
                'virtualmachineid' => instance_id,
              }
              options.merge!('deviceid' => mountpoint) if mountpoint

              data = service.attach_volume(options)

                                            service.jobs.new(data["attachvolumeresponse"])
            end