anchor.diff:  -spec export_seed() -> undefined | {alg(), alg_seed()}.
   export_seed() ->
       case seed_get() of
  -	{#alg{type=Alg}, Seed} -> {Alg, Seed};
  +	{#{type:=Alg}, Seed} -> {Alg, Seed};
   	_ -> undefined
       end.
   
   -spec export_seed(state()) -> {alg(), alg_seed()}.
  -export_seed({#alg{type=Alg}, Seed}) -> {Alg, Seed}.
  +export_seed({#{type:=Alg}, Seed}) -> {Alg, Seed}.
   
   %% seed0/0: returns the default state, including the state values
   %% and the algorithm handler.
  
positive.code: %% This depends on the algorithm handler function
  -type alg_seed() :: any().
  %% This is the algorithm handler function within this module
  -type alg_handler() :: #alg{}.
  %% Internal state
  -type state() :: {alg_handler(), alg_seed()}.
  
  
negative.code: %% and a new state.
  
  -spec uniform_s(state()) -> {float(), NewS :: state()}.
  uniform_s({Alg = #{uniform:=Uniform}, AS0}) ->
      {X, AS} = Uniform(AS0),
      {X, {Alg, AS}}.
  
  