code: function checkPartition(obj) {
    var count = 0
    Object.keys(obj).forEach(key=> {
      if (obj[key] === '*String') count += 1
      if (obj[key] === '*Number') count += 1
    })
    return count === 1
  }
docs: tables must have one partition key of either *String or *Number expects {someKey:'*String', someOtherKey:'**String', insert: 'Lambda'}