anchor.diff:      [{ct_hooks, [ts_install_cth]}].
   
   all() ->
  -    [t_get_3,
  +    [t_get_3,t_filter_2,
        t_fold_3,t_map_2,t_size_1,
        t_with_2,t_without_2].
   
  
positive.code: -export([init_per_testcase/2]).
  -export([end_per_testcase/2]).
  
  -export([t_get_3/1,
           t_fold_3/1,t_map_2/1,t_size_1/1,
           t_with_2/1,t_without_2/1]).
  
  
negative.code:     ?badarg(with,[a,#{}]) = (catch maps:with(a,#{})),
      ok.
  
  t_filter_2(Config) when is_list(Config) ->
      M = #{a => 2, b => 3, c=> 4, "a" => 1, "b" => 2, "c" => 4},
      Pred1 = fun(K,V) -> is_atom(K) andalso (V rem 2) =:= 0 end,
      Pred2 = fun(K,V) -> is_list(K) andalso (V rem 2) =:= 0 end,
      #{a := 2,c := 4} = maps:filter(Pred1,M),
      #{"b" := 2,"c" := 4} = maps:filter(Pred2,M),
      %% error case
      ?badmap(a,filter,[_,a]) = (catch maps:filter(fun(_,_) -> ok end,id(a))),
      ?badarg(filter,[<<>>,#{}]) = (catch maps:filter(id(<<>>),#{})),
      ok.
  
  t_fold_3(Config) when is_list(Config) ->
      Vs = lists:seq(1,200),
  