anchor.diff:  remove(_,_) -> erlang:nif_error(undef).
   
   
  -%% Shadowed by erl_bif_types: maps:to_list/1
   -spec to_list(Map) -> [{Key,Value}] when
       Map :: map(),
       Key :: term(),
  
positive.code: find(_,_) -> erlang:nif_error(undef).
  
  
  %% Shadowed by erl_bif_types: maps:from_list/1
  -spec from_list([{Key,Value}]) -> Map when
      Key :: term(),
      Value :: term(),
      Map :: map().
  
negative.code: 
  -compile(no_native).
  
  -spec get(Key,Map) -> Value when
      Key :: term(),
      Map :: map(),
  