anchor.diff:      if (value is Map) return _replaceEnvInMap(value);
       var matcher = new RegExp(r'^env\(\s*(.*?)\s*(?:,\s*(.*?))?\s*\)$');
       if (value is! String || !matcher.hasMatch(value)) return value;
  -    return (value as String).replaceFirstMapped(matcher, (m) {
  -      var envName = m[1];
  -      var defaultValue = m[2];
  -      return _cast(env(envName, defaultValue));
  -    });
  +    final m = matcher.firstMatch(value);
  +    var envName = m[1];
  +    var defaultValue = m[2];
  +    return _cast(env(envName, defaultValue));
     }
   
     Object _cast(String env) {
  
positive.code:   static _loadEnv() {
      try {
        dotenv.load();
      } on FileSystemException {
      }
      _envHasBeenLoaded = true;
    }
  
  
negative.code: 
    _childOfItemByKey(item, key) {
      return (item is Iterable)
          ? item[int.parse(key)]
          : item[key];
    }
  
    String toString() {
  