anchor.diff:      A   = maps:from_list([]),
       0   = erlang:map_size(A),
   
  -    #{a:=1,b:=2}  = maps:from_list([{a,1},{b,2}]),
  +    #{a:=1,b:=2}      = maps:from_list([{a,1},{b,2}]),
       #{c:=3,a:=1,b:=2} = maps:from_list([{a,1},{b,2},{c,3}]),
       #{g:=3,a:=1,b:=2} = maps:from_list([{a,1},{b,2},{g,3}]),
   
  
positive.code: 
  t_bif_map_to_list(Config) when is_list(Config) ->
      [] = maps:to_list(#{}),
      [{a,1},{b,2}] = maps:to_list(#{a=>1,b=>2}),
      [{a,1},{b,2},{c,3}] = maps:to_list(#{c=>3,a=>1,b=>2}),
      [{a,1},{b,2},{g,3}] = maps:to_list(#{g=>3,a=>1,b=>2}),
      [{a,1},{b,2},{g,3},{"c",4}] = maps:to_list(#{g=>3,a=>1,b=>2,"c"=>4}),
      [{3,v2},{hi,v4},{{hi,3},v5},{"hi",v3},{<<"hi">>,v1}] = maps:to_list(#{
  	    <<"hi">>=>v1,3=>v2,"hi"=>v3,hi=>v4,{hi,3}=>v5}),
  
      [{3,v7},{hi,v9},{{hi,3},v10},{"hi",v8},{<<"hi">>,v6}] = maps:to_list(#{
  	    <<"hi">>=>v1,3=>v2,"hi"=>v3,hi=>v4,{hi,3}=>v5,
  	    <<"hi">>=>v6,3=>v7,"hi"=>v8,hi=>v9,{hi,3}=>v10}),
  
      %% error cases
      {'EXIT', {badarg,_}} = (catch maps:to_list(id(a))),
  
negative.code:     {'EXIT',{badarg,[{maps,put,_,_}|_]}} = (catch maps:put(1,a,atom)),
      {'EXIT',{badarg,[{maps,put,_,_}|_]}} = (catch maps:put(1,a,[])),
      {'EXIT',{badarg,[{maps,put,_,_}|_]}} = (catch maps:put(1,a,<<>>)),
      ok.
  
  is_members([],_) -> true;
  is_members([K|Ks],Ls) ->
      lists:member(K,Ls) andalso is_members(Ks,Ls).
  
  t_bif_map_remove(Config) when is_list(Config) ->
      0  = erlang:map_size(maps:remove(some_key, #{})),
  