code: public void remove(String keyStr) {
  
      List<String> keys = split(keyStr, '.');
      int numKeys = keys.size();
  
      CollectionData collectionData = this;
      for (int i = 0; i <= numKeys - 2; ++i) {
        SoyData soyData = collectionData.getSingle(keys.get(i));
        if (!(soyData instanceof CollectionData)) {
          return;
        }
        collectionData = (CollectionData) soyData;
      }
  
      collectionData.removeSingle(keys.get(numKeys - 1));
    }
docs: Removes the data at the specified key string.
  
  @param keyStr One or more map keys and/or list indices (separated by '.' if multiple parts).
  Indicates the path to the location within this data tree.