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)
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.