anchor.diff:      rewrap(Tail, {[Fn|Fns], Props ++ AccProps}).
   
   to_num(N) when is_number(N) -> N;
  +to_num(<<"ln(2)">>) -> math:log(2);
   to_num(<<"pi">>) -> math:pi();
   to_num(<<"e">>) -> math:exp(1).
  
positive.code:                     tgs:call_fun("complex_numbers:new", lists:map(fun tgs:value/1, Cplx))]))])]),
  
      {ok, Fn, [{Property, ["Z"]}]};
  generate_test(#{description := Desc, expected := Exp, property := Prop, input := Z}) ->
      TestName = tgen:to_test_name(Desc),
      Property = binary_to_list(Prop),
  
  
negative.code:                     tgs:call_fun("complex_numbers:new", lists:map(fun tgs:value/1, Cplx))])])])]),
  
      {ok, Fn, [{Property, ["Z"]}]};
  generate_test(#{description := Desc, expected := Exp, property := <<"div">>, input := #{z1 := Z1, z2 := Z2}}) ->
      generate_test(#{description => Desc, expected => Exp, property => <<"divide">>, input => #{z1 => Z1, z2 => Z2}});
  generate_test(#{description := Desc, expected := Exp, property := Prop, input := #{z1 := Z1, z2 := Z2}}) ->
      TestName = tgen:to_test_name(Desc),
      Property = binary_to_list(Prop),
  
  