Error trying to Sample the Prior


I’m trying to plot the prior predictive. When I run az.plot_ppc(trace_9, group="prior", kind = 'cumulative', observed=True), it runs fine and looks like thus:

But when I take the ‘cumulative’, I get the following error:

ValueError                                Traceback (most recent call last)
/tmp/ipykernel_15407/ in <module>
----> 1 az.plot_ppc(trace_9, group="prior", observed=True)

/opt/conda/lib/python3.7/site-packages/arviz/plots/ in plot_ppc(data, kind, alpha, mean, observed, color, colors, grid, figsize, textsize, data_pairs, var_names, filter_vars, coords, flatten, flatten_pp, num_pp_samples, random_seed, jitter, animated, animation_kwargs, legend, labeller, ax, backend, backend_kwargs, group, show)
    354     # TODO: Add backend kwargs
    355     plot = get_plotting_function("plot_ppc", "ppcplot", backend)
--> 356     axes = plot(**ppcplot_kwargs)
    357     return axes

/opt/conda/lib/python3.7/site-packages/arviz/plots/backends/matplotlib/ in plot_ppc(ax, length_plotters, rows, cols, figsize, animated, obs_plotters, pp_plotters, predictive_dataset, pp_sample_ix, kind, alpha, colors, textsize, mean, observed, jitter, total_pp_samples, legend, labeller, group, animation_kwargs, num_pp_samples, backend_kwargs, show)
    166                 else:
    167                     bins = get_bins(vals)
--> 168                     _, hist, bin_edges = histogram(vals, bins=bins)
    169                     hist = np.concatenate((hist[:1], hist))
    170                     pp_densities.append(hist)

/opt/conda/lib/python3.7/site-packages/arviz/ in __call__(self, *args, **kwargs)
    193         """Call the jitted function or normal, depending on flag."""
    194         if Numba.numba_flag:
--> 195             return self.numba_fn(*args, **kwargs)
    196         else:
    197             return self.function(*args, **kwargs)

and prints this:

Why does one work and not the other?