How do you add the weight of an observation to a Mixed Model? I thought I could add the Freq column to wt argument, but apparently not.

```
using RDatasets MixedModels
titanic = RDatasets.dataset("datasets", "Titanic")
titanic.surv_flg = titanic.Survived .== "Yes";
```

This runs:

```
MixedModels.fit(GeneralizedLinearMixedModel, @formula(surv_flg ~ 1 + Age + Sex + (1 | Class)), titanic, Bernoulli(), nAGQ = 2, fast = true)
```

But this doesnβt

```
MixedModels.fit(GeneralizedLinearMixedModel, @formula(surv_flg ~ 1 + Age * Sex + (1 | Class)), titanic, wt = Freq, Bernoulli(), nAGQ = 2, fast = true)
```