anchor.diff:  
   %% Internal exports
   %% -export([]).
  +
  +
  +-type evaluator_state() :: term().
  +-type command_fun() :: 
  +        fun((State :: evaluator_state()) -> ok) |
  +        fun((State :: evaluator_state()) -> {ok, evaluator_state()}) |
  +        fun((State :: evaluator_state()) -> {error, term()}).
  +
  +-type command() :: #{desc  := string(),
  +                     cmd   := command_fun()
  +                    }.
   
   
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
positive.code: 
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  sock_open(Domain, Type, Proto) ->
      try socket:open(Domain, Type, Proto) of
          {ok, Socket} ->
  
negative.code:     [];
  api_b_open_and_close_udp4(_Config) when is_list(_Config) ->
      tc_begin(api_b_open_and_close_udp4),
      State = #{domain   => inet,
                type     => dgram,
                protocol => udp},
      ok = api_b_open_and_close(State),
      tc_end().
  
  
  