protected boolean arvoreBinariaBuscaValidaAux(Nodo nodo){
        if(nodo != null){
            Nodo left = nodo.getLeft();
            Nodo right = nodo.getRight();
            if((left != null && left.getKey() > nodo.getKey()) || (right != null && right.getKey() < nodo.getKey())){
                return false;
            }
            else{
                return (true && arvoreBinariaBuscaValidaAux(left) && arvoreBinariaBuscaValidaAux(right));
            }
        }
        else{
            return true;
        }
    }