title: DynamoDBObjectModel error when attempting read from DynamoDB (Swift)
body: <p>Just getting started with DynamoDB and I'm following their Swift examples and I keep getting the same error: <em>'NSInternalInconsistencyException', reason: '_regionId is not a property of TestApp.RegionLocations.'</em></p>
  
  <p>My DynamoDB item with the partition key <em>regionId</em> looks like this:</p>
  
  <pre><code>{
    "locations": [
      {
        "latitude": 40.1234567,
        "longitude": 70.1234567,
        "name": "Location 1",
        "locationId": "LOCATION1-123"
      },
      {
        "latitude": 41.1234567,
        "longitude": 71.12345678,
        "name": "Location 2",
        "locationId": "Location2-123"
      }
  ],
    "regionId": "region1"
  }
  </code></pre>
  
  <p>The DynamoDBObjectModel downloaded from AWS. Completely untouched be me:</p>
  
  <pre><code>import Foundation
  import UIKit
  import AWSDynamoDB
  
  class RegionLocations: AWSDynamoDBObjectModel, AWSDynamoDBModeling {
  
      var _regionId: String?
      var _locations: [String: String]?
  
      class func dynamoDBTableName() -&gt; String {
  
          return -nameOfTable-
      }
  
      class func hashKeyAttribute() -&gt; String {
  
          return "_regionId"
      }
  
        override class func jsonKeyPathsByPropertyKey() -&gt; [AnyHashable: Any] {
            return [
                 "_regionId" : "regionId",
                 "_locations" : "locations",
        ]
      }
    }
  </code></pre>
  
  <p>Fetching function which is called in the ViewDidLoad() of my VC. Basically copied from AWS's example with changed variable names and <em>rangeKey: nil</em> :</p>
  
  <pre><code>func fetchLocations(){
  
      let dynamoDbObjectMapper = AWSDynamoDBObjectMapper.default()
      let locations: RegionLocations = RegionLocations();
      locations._regionId = "region1"
  
      dynamoDbObjectMapper.load(
          RegionLocations.self,
          hashKey: locations._regionId!,
          rangeKey: nil,
          completionHandler: {
              (objectModel: AWSDynamoDBObjectModel?, error: Error?) -&gt; Void in
              if let error = error {
                  print("Amazon DynamoDB Read Error: \(error)")
                  return
              }
              print("An item was read.")
      })
  }
  </code></pre>
  
  <p>Have tried (w/o success) with : hashKey: "region1" inside of dynamoDbObjectMapper.load() instead of using the RegionLocations object in the code above.
  Have also restarted Xcode and cleaned the project multiple times.
  I'm very confused on what I'm doing wrong since I'm mostly following AWS's tutorial.</p>