code: protected function required($objectName)
      {
          $method = "get{$objectName}";
          $class = "Basho\\Riak\\{$objectName}";
          $value = $this->$method();
          if (is_null($value)) {
              throw new Builder\Exception("Expected non-empty value for {$objectName}");
          }
          if (is_object($value) && $value instanceof $class === false) {
              throw new Builder\Exception("Expected instance of {$class}, received instance of " . get_class($value));
          }
          if (is_array($value) && count($value) == 0) {
              throw new Builder\Exception("Expected non-empty array value for {$objectName}");
          }
      }
docs: Used to verify a property within the builder is not null and is instantiated
  
  @param $objectName
  
  @throws Builder\Exception