Cannot convince StanSample to change num_samples

General Usage
1

This is a simple model:

art_model = "
  data {
    int<lower = 0, upper = 100> Y;
  }
  parameters {
    real<lower = 0, upper = 1> pi;
  }
  model {
    Y ~ binomial(100, pi);
    pi ~ beta(4, 6);
}
"""

sample_art_model = SampleModel("artSim", art_model, tmpdir)

(I have already defined tmpdir)

Now, I want to sample 5000 warmups and 5000 samples out of this, but I cant.

data = (Y=14,)

art_sim = stan_sample(sample_art_model; data=data,num_warmups = 5000,
  num_samples=5000, num_chains=4, seed = 84735, sig_figs=18)

if success(art_sim)
  art_sim_summary = read_summary(sample_art_model, true)
  art_sim_df = read_samples(sample_art_model, :dataframes)
  art_sim_summary |> display
end

The vector w/ the samples, art_sim_df, does contain 4 dataframes, and each of them contains 5000 elements BUT 4000 of them are 0:

julia > [count(==(0.), art_sim_df[i].pi) for i in 1:4]
4-element Vector{Int64}:
 4000
 4000
 4000
 4000

I’ve also tried setting the num_sample param directly in the struct,
sample_art_model.num_samples = 5000
but to no avail.
It seems that the default value for num_samples (which is 1000) always prevails.

Any ideas what I am doing wrong?

Dim