UserScheduleTypeResolver:
    Type: AWS::AppSync::Resolver
    DependsOn: SessionManagerSchema
    Properties:
      ApiId: !GetAtt SessionManagerApi.ApiId
      TypeName: UserSchedule
      FieldName: Sessions
      DataSourceName: !GetAtt SessionsTableDataSource.Name
      RequestMappingTemplate: !Sub |
        #set($ids = [])
        #foreach($item in ${!ctx.source.items})
          #set($map = {})
          $util.qr($map.put("SessionId", $util.dynamodb.toString($item.SessionId)))
          $util.qr($ids.add($map))
        #end

        {
          "version" : "2018-05-29",
          "operation" : "BatchGetItem",
          "tables" : {
            "${DDBSessionsTable}": {
              "keys": $util.toJson($ids),
              "consistentRead": true
            }
          }
        }
      ResponseMappingTemplate: !Sub |
        $util.toJson($ctx.result.data.${DDBSessionsTable})