Improvement on Posteriors Comparison Across Models

[edwinnglabs]

Is your feature request related to a problem? Please describe.
Right now we have

params_comparison_boxplot(
        ['Default', 'Smaller Sigma'],
        [np.stack([ps['trend.unemploy'].flatten(), ps['trend.filling'].flatten(), ps['trend.job'].flatten()]).transpose(),
         np.stack([ps_smaller_prior['trend.unemploy'].flatten(), ps_smaller_prior['trend.filling'].flatten(), ps_smaller_prior['trend.job'].flatten()]).transpose()],
        ['trend.unemploy', 'trend.filling', 'trend.job'],
        box_width = .1, box_distance=0.1,
        showfliers=True
);

under https://orbit-ml.readthedocs.io/en/latest/tutorials/model_diagnostics.html

The code chunk with the np.stack, flatten, transpose looks complicated to me. Could we have something similar to the utilization of arviz (check the previous code block under same demo page).