protected static function getDynamoDbKey(DynamoDbModel $model, $id)
 {
     $keyName = $model->getKeyName();
     $idKey = $model->marshalItem([$keyName => $id]);
     $key = [$keyName => $idKey[$keyName]];
     return $key;
 }
 protected static function getSpecificDynamoDbKey(DynamoDbModel $model, $keyName, $value)
 {
     $idKey = $model->marshalItem([$keyName => $value]);
     $key = [$keyName => $idKey[$keyName]];
     return $key;
 }