docs: def plot_sediment_memory(self, ax=None):
          """Plot sediment memory prior and posterior distributions"""
          if ax is None:
              ax = plt.gca()
  
          y_prior, x_prior = self.prior_sediment_memory()
          ax.plot(x_prior, y_prior, label='Prior')
  
          y_posterior = self.mcmcfit.sediment_memory
          density = scipy.stats.gaussian_kde(y_posterior ** (1/self.thick))
          density.covariance_factor = lambda: 0.25
          density._compute_covariance()
          ax.plot(x_prior, density(x_prior), label='Posterior')
  
          mem_mean = self.mcmcsetup.mcmc_kws['mem_mean']
          mem_strength = self.mcmcsetup.mcmc_kws['mem_strength']
          annotstr_template = 'mem_strength: {0}\nmem_mean: {1}\nthick: {2} cm'
          annotstr = annotstr_template.format(mem_strength, mem_mean, self.thick)
          ax.annotate(annotstr, xy=(0.9, 0.9), xycoords='axes fraction',
                      horizontalalignment='right', verticalalignment='top')
  
          ax.set_ylabel('Density')
          ax.set_xlabel('Memory (ratio)')
          ax.grid(True)
          return ax