code: public void removeFeature(FeatureInterface<AbstractSequence<C>, C> feature) {
  		features.remove(feature);
  		ArrayList<FeatureInterface<AbstractSequence<C>, C>> featureList = groupedFeatures.get(feature.getType());
  		if (featureList != null) {
  			featureList.remove(feature);
  			if (featureList.isEmpty()) {
  				groupedFeatures.remove(feature.getType());
  			}
  		}
  	}
docs: Remove a feature from the sequence
  @param feature