anchor.diff:     * Throws [ArgumentError] if configuration with [name] does not exists.
      */
     Map get(name) {
  -    if (_configurations.containsKey(name)) throw new ArgumentError("Configuration does not exist");
  +    if (!_configurations.containsKey(name)) throw new ArgumentError("Configuration does not exist");
       var config = _configurations[name];
       if (config["parent"] == null) {
  -
  +      return config["configMap"].toMap();
  +    } else {
  +      return mergeMaps(get(config["parent"]), config["configMap"]);
       }
     }
   }
positive.code:   }
  
    Map toMap() {
      var res = new Map.from(_data);
      _data.forEach((k,v) {
  
      });
    }
  
    ConfigMap.config(ConfigMap this.root, Map this._data);
  
negative.code: 
  class ComputedValue {
    final _computation;
    bool _evaluated = false;
    dynamic _value;
    ComputedValue(dynamic this._computation(ConfigMap config));
  
  