@spec actor_of_initial_seat(non_neg_integer()) :: t()

@spec all() :: [t()]

@spec all(Riichi.Rules.t()) :: [t()]

@spec all_after(t()) :: [t()]

@spec for_each(Riichi.Rules.t(), (t() -> k)) :: %{required(t()) => k} when k: var

@spec initial_seat_of_actor(t()) :: 1..3

@spec next(t(), Riichi.Rules.t()) :: t()