I need to put this objective function in Julia, but I don’t know how to build a sum that has 3 indexes. Can someone help me?

I started doing like this

```
using JuMP, Cbc
Model1 = Model(with_optimizer(Cbc.Optimizer))
CR = [11; 11; 11; 11; 11]
CO = [50; 50; 50; 50; 50]
#sets
a = 80 #atividades
t = 18 #peírodo de tempo
w = 5 #centro de trabalho
#variable
@variable(Model1,r[1:a,1:t], lower_bound=0)
@variable(Model1,o[1:a,1:t], lower_bound=0)
#objective function
@objective(Model1,Min,sum(CR[w]*(r[a,t]+o[a,t])+CO[w]*o[a,t]))
```