`[.ranked_ballots`      Access Subsets of Ballots.
dirichlet_tree          Create a Dirichlet-tree for modelling ranked
                        ballots
dirtree                 Create a Dirichlet-tree object
ranked_ballots          Construct a set of ranked ballots.
read_ballots            Read 'ranked_ballots' from a file.
reset                   Clear the internal state of a 'dirichlet_tree'
                        object.
sample_posterior        Draw election outcomes from the posterior
                        distribution.
sample_predictive       Draw ballots from the posterior predictive
                        distribution.
social_choice           Election Social Choice Functions
update                  Update a 'dirichlet_tree' model by observing
                        some ranked ballots.
write_ballots           Write 'ranked_ballots' to a file.
