anchor.diff:  translate_posting_filter(undefined) ->
       undefined;
   translate_posting_filter(#'PostingFilter'{sort_by = 'RELEVANCE',
  -					  start_ts = 0,
  -					  end_ts = 0,
  +					  start_ts = <<>>,
  +					  end_ts = <<>>,
   					  max_postings = 0}) ->
       undefined;
   translate_posting_filter(#'PostingFilter'{sort_by = SortBy,
  
positive.code:     {null, <<>>};
  make_value(A) when is_atom(A) ->
      {string, atom_to_list(A)};
  make_value(T) when is_tuple(T) ->
      {binary, term_to_binary(T)}.
  
  
negative.code: validate_attributes(["num_of_shards" | T], Acc) ->
      validate_attributes(T, [num_of_shards | Acc]);
  validate_attributes(["nodes" | T], Acc) ->
      validate_attributes(T, [index_on | Acc]);
  validate_attributes(["index_on" | T], Acc) ->
      validate_attributes(T, [index_on | Acc]);
  validate_attributes([_H | T], Acc) ->
      validate_attributes(T, Acc).
  
  