.warner                 Temporary helper function to warn about
                        argument order change
cowstates               Correlates of War list of independent states
gwstates                Gleditsch and Ward list of independent states
id_date_sequence        Identify date sequences
plot_missing            Visualize missing and non-proper cases for
                        state panel data
polity                  Polity IV combined Polity scores
sfind                   Lookup country codes or names
state_panel             Create state panel data
states                  State system membership
