anchor.diff:      lists:reverse(erase(?MODULE)).
   
   id(I) -> I.
  -    
  +
   fc(Args, {'EXIT',{function_clause,[{?MODULE,_,Args,_}|_]}}) -> ok;
   fc(Args, {'EXIT',{function_clause,[{?MODULE,_,Arity,_}|_]}})
     when length(Args) =:= Arity ->
  
positive.code:     ok.
  
  effect(Config) when is_list(Config) ->
      [{42,{a,b,c}}] =
  	do_effect(fun(F, L) ->
  			  [F({V1,V2}) ||
  
negative.code:     [{ct_hooks,[ts_install_cth]},
       {timetrap,{minutes,1}}].
  
  all() ->
      test_lib:recompile(?MODULE),
      [{group,p}].
  
  groups() ->
      [{p,test_lib:parallel(),
        [basic,
         deeply_nested,
  