code: public static NestedListContainer eliminateEmptyStructures( NestedListContainer nlc ){
  		for(int i=nlc.size()-1; i>=0; i--){
  			NestedList nl = nlc.getNestedList(i);
  			if( nl.getClass()==NestedListContainer.class )
  				eliminateEmptyStructures( (NestedListContainer)nl );
  			
  			if( nl.empty() )nlc.remove( nl );			
  		}
  		return nlc;
  	}
docs: Removes all empty Structures from a NestedListContainer and all substructures.