anchor.diff:  -spec create_val_50rand_50coll(
           ParseState::tester_parse_state:state(),
           Getter::fun((tester_parse_state:state()) -> {Length::non_neg_integer(), Values::[T]}),
  -        RandVal::T) -> T.
  -create_val_50rand_50coll(ParseState, Getter, RandVal) ->
  +        RandValFun::fun(() -> T)) -> T.
  +create_val_50rand_50coll(ParseState, Getter, RandValFun) ->
       case crypto:rand_uniform(0, 2) of
           0 -> % take one of the collected values (if possible)
               {Length, Values} = Getter(ParseState),
               case Length of
  -                0 -> RandVal;
  +                0 -> RandValFun();
                   _ -> lists:nth(crypto:rand_uniform(1, Length + 1), Values)
               end;
           1 ->
  -            RandVal
  +            RandValFun()
       end.
  
positive.code: create_value(atom, _Size, ParseState) ->
      create_val_50rand_50coll(
        ParseState, fun tester_parse_state:get_atoms/1,
        lists:nth(crypto:rand_uniform(1, 5), [one, two, three, four]));
  create_value(float, _Size, ParseState) ->
      create_val_50rand_50coll(
        ParseState, fun tester_parse_state:get_floats/1,
        crypto:rand_uniform(-5, 5) * (crypto:rand_uniform(0, 30323) / 30323.0));
  create_value({range, {integer, Low}, {integer, High}}, _Size, _ParseState) ->
      crypto:rand_uniform(Low, High + 1);
  create_value({union, Types}, Size, ParseState) ->
  
negative.code: create_value(binary, Size, ParseState) ->
      create_val_50rand_50coll(
        ParseState, fun tester_parse_state:get_binaries/1,
        fun() -> list_to_binary(create_value({list, {range, {integer, 0}, {integer, 16#ff}}}, Size, ParseState)) end);
  create_value(bool, _Size, _ParseState) ->
      case crypto:rand_uniform(0, 2) of
          0 -> false;
  