code: public boolean isHomomeric() {
  		EntityInfo first = getParentChains().getFirst().getEntityInfo();
  		EntityInfo second = getParentChains().getSecond().getEntityInfo();
  		if (first==null || second==null) {
  			logger.warn("Some compound of interface {} is null, can't determine whether it is homo/heteromeric. Consider it homomeric", getId());
  			return true;
  		}
  		return
  			first.getRepresentative().getId().equals(second.getRepresentative().getId());
  	}
docs: Returns true if the 2 molecules of this interface are the same entity (i.e. homomeric interface), false
  otherwise (i.e. heteromeric interface)
  @return true if homomeric or if either of the entities is unknonw (null Compounds), false otherwise