public double avgDepth(int d) {
double total = 0.0;
for (Exp e : exps) total += e.avgDepth(d + 1);
return total / exps.size();
}
public double avgDepth(int d) {
double total = 0.0;
for (Exp e : exps) total += e.avgDepth(d + 1);
return total / exps.size();
}