public boolean validarFeed(Feed feed) throws ObjetoNuloException{
        
        if(feed == null){
            throw  new ObjetoNuloException("Feed is null");
        }
        if(feed.getDescription().equals("")){
            throw  new ObjetoNuloException("Feed.description is null");
        }
        if(feed.getLink().equals("")){
            throw  new ObjetoNuloException("Feed.link is null");
        }
        if(feed.getTitle().equals("")){
            throw  new ObjetoNuloException("Feed.title is null");
        }
        
        
        return true;
    }