code: public Set<ModificationFeature> getModifications()
  	{
  		Set<ModificationFeature> set = new HashSet<ModificationFeature>();
  
  		for (PhysicalEntity pe : pes)
  		{
  			set.addAll(PE2FEAT.getValueFromBean(pe));
  		}
  		return set;
  	}
docs: Collects modifications from the elements of the chain.
  @return modifications