anchor.diff:  
   -spec from_json(cowboy_req:req(), state()) ->
       {boolean(), cowboy_req:req(), state()}.
  -from_json(Req, #state{}) ->
  +from_json(Req, State) ->
       case get_vars_from_body(Req) of
  -        {ok, State, Req2} ->
  -            ModuleName = State#state.module_name,
  -            ModuleSource = State#state.module_source,
  +        {ok, {ModuleName, ModuleSource}, Req2} ->
               ScenarioPath = "scenarios/" ++ erlang:binary_to_list(ModuleName),
               file:write_file(
                 ScenarioPath ++ ".erl",
  
positive.code: 
  -spec rest_init(cowboy_req:req(), [atom()]) -> {ok, cowboy_req:req(), state()}.
  rest_init(Req, _Opts) ->
      {ok, Req, #state{}}.
  
  -spec allowed_methods(cowboy_req:req(), state()) -> 
      {[binary()], cowboy_req:req(), state()}.
  
negative.code: 
  -spec to_json(cowboy_req:req(), state()) -> 
      {jsx:json_text(), cowboy_req:req(), state()}.
  to_json(Req0, State) ->
      {ok, Filenames} = file:list_dir("scenarios"),
      Filenames2 =
          lists:filter(
  