code: def plot_bf(
      ax,
      bf_10,
      bf_01,
      prior,
      posterior,
      ref_val,
      prior_at_ref_val,
      posterior_at_ref_val,
      var_name,
      colors,
      figsize,
      textsize,
      plot_kwargs,
      hist_kwargs,
      backend_kwargs,
      show,
  ):
      """Matplotlib Bayes Factor plot."""
      if backend_kwargs is None:
          backend_kwargs = {}
  
      if hist_kwargs is None:
          hist_kwargs = {}
  
      backend_kwargs = {
          **backend_kwarg_defaults(),
          **backend_kwargs,
      }
  
      figsize, _, _, _, linewidth, _ = _scale_fig_size(
          figsize, textsize, 1, 1
      )
  
      plot_kwargs = matplotlib_kwarg_dealiaser(plot_kwargs, "plot")
      plot_kwargs.setdefault("linewidth", linewidth)
      hist_kwargs.setdefault("alpha", 0.5)
  
      backend_kwargs.setdefault("figsize", figsize)
      backend_kwargs.setdefault("squeeze", True)
  
      if ax is None:
          _, ax = create_axes_grid(1, backend_kwargs=backend_kwargs)
  
      plot_dist(
          prior,
          color=colors[0],
          label="Prior",
          ax=ax,
          plot_kwargs=plot_kwargs,
          hist_kwargs=hist_kwargs,
      )
      plot_dist(
          posterior,
          color=colors[1],
          label="Posterior",
          ax=ax,
          plot_kwargs=plot_kwargs,
          hist_kwargs=hist_kwargs,
      )
  
      ax.plot(ref_val, posterior_at_ref_val, "ko", lw=1.5)
      ax.plot(ref_val, prior_at_ref_val, "ko", lw=1.5)
      ax.axvline(ref_val, color="k", ls="--")
      ax.set_xlabel(var_name)
      ax.set_ylabel("Density")
      ax.set_title(
          f"The BF_10 is {bf_10:.2f}\nThe BF_01 is {bf_01:.2f}"
      )
      plt.legend()
  
      if backend_show(show):
          plt.show()
  
      return ax
  
imports: import matplotlib.pyplot
  from .None import backend_kwarg_defaults, backend_show, create_axes_grid, matplotlib_kwarg_dealiaser
  from ...distplot import plot_dist
  from ...plot_utils import _scale_fig_size
label_desc: Use image node_id 1 for calling a global function with example usage: plot_bf(ax, bf_10, bf_01, prior, posterior, ref_val, prior_at_ref_val, posterior_at_ref_val, var_name, colors, figsize, textsize, plot_kwargs, hist_kwargs, backend_kwargs, show) and returns: ax