anchor.diff:  -module(boss_db_adapter_mongodb).
   -behaviour(boss_db_adapter).
  +-include_lib("mongodb/include/mongo_protocol.hrl").
   -export([start/1, stop/0, init/1, terminate/1, find/2, find/7]).
   -export([count/3, counter/2, incr/2, incr/3, delete/2, save_record/2]).
   -export([execute/2, transaction/2]).
  
positive.code:     mongo_regex_options_for_re_module_options(Rest, [$m|Acc]).
  
  % Boss and MongoDB have a different conventions to id attributes (id vs. '_id').
  -spec(attr_value(id|string(), proplist('_id'|string(),string())) -> string()|undefined).
  attr_value(id, MongoDoc) ->
      proplists:get_value('_id', MongoDoc);
  attr_value(AttrName, MongoDoc) ->
  
negative.code:         {ok, {Doc}} -> 
              PropList = tuple_to_proplist(Doc),
              proplists:get_value(value, PropList);
          {failure, Reason} -> {error, Reason}
          
      end.
  
  incr(Conn, Id) ->
  