code: public boolean sameAs(Object obj){
  		if(obj==null){
  			return false;
  		}
  		if(obj instanceof String || obj instanceof IdVersionString){
  			if(this.toString().equals(obj.toString())){
  				return true;
  			}
  		}
  		return false;
  	}
docs: Tests if the parameter is the same id and version.
  @param obj object to test
  @return true if the parameter is an IdVersionString or a string with the same identifier and the same version, false otherwise