anchor.diff:  %% Function: add_field_internal/3
   %% @end
   add_field_internal(Json, Field, Value) ->
  -    Attrs = parse_attr(Field),
  -    
  +    Attrs = parse_attr(Field),    
       try erlson:store(Attrs, Value, Json) of
   	NewJson ->
   	    to_string(erlson:to_json(NewJson))
  
positive.code: %% Function: add_value_internal/3
  %% @end
  add_value_internal(Json, Field, Value) ->
      Attrs = parse_attr(Field),    
      try erlson:store(Attrs, Value, Json) of
  	NewJson ->
  	    to_string(erlson:to_json(NewJson))
      catch
  	_:_ ->
  	    to_string(erlson:to_json(Json))
  
negative.code: %% @type attr() = atom() | string()
  -type attr() :: atom() | string().
  %% @type field() = json_string() | mochijson()
  -type field() :: atom() | string() | [atom()].
  %% @type json() = json_string() | mochijson()
  -type json() :: json_string() | mochijson().
  %% @type json_string() = string()
  