docs: def compute_distances(self, model, alpha=None, ncat=4, tolerance=1e-6):
          """
          Compute pairwise distances between all sequences according to
          a given substitution model, `model`, of type phylo_utils.models.Model
          (e.g. phylo_utils.models.WAG(freqs), phylo_utils.models.GTR(rates, freqs))
          The number of gamma categories is controlled by `ncat`. Setting ncat=1
          disable gamma rate variation. The gamma alpha parameter must be supplied
          to enable gamma rate variation.
          """
          return pairdists(self, model, alpha, ncat, tolerance)