docs: def prior_sediment_rate(*args, **kwargs):
          """Get the prior density of sediment rates
  
          Returns
          -------
          y : ndarray
              Array giving the density.
          x : ndarray
              Array of sediment accumulation values (yr/cm) over which the density was evaluated.
          """
          # PlotAccPrior @ Bacon.R ln 113 -> ln 1097-1115
          # alpha = acc_shape, beta = acc_shape / acc_mean
          # TODO(brews): Check that these stats are correctly translated to scipy.stats distribs.
          acc_mean = kwargs['acc_mean']
          acc_shape = kwargs['acc_shape']
          x = np.linspace(0, 6 * np.max(acc_mean), 100)
          y = stats.gamma.pdf(x, a=acc_shape,
                              scale=1 / (acc_shape/acc_mean))
          return y, x