docs: public static <StrategyVisitor extends Visitor> StrategyVisitor visitAll( Iterable<? extends Visitable> visitables,
                                                                                StrategyVisitor strategyVisitor ) {
          if (visitables != null) {
              for (Visitable visitable : visitables) {
                  if (visitable != null) {
                      visitable.accept(new WalkAllVisitor(strategyVisitor));
                  }
              }
          }
          return strategyVisitor;
      }