anchor.diff:    }, SetOpts),
     mc_connection_man:process_reply(Doc, Command).
   
  -
  -%% @private
   prepare_and_assign(Docs) when is_tuple(Docs) ->
     case element(1, Docs) of
       <<"$", _/binary>> -> Docs;  %command
  
positive.code:     List -> List
    end.
  
  %% @private
  %% Convert maps or proplists to bson
  prepare_doc(Docs) when is_list(Docs) ->  %list of documents
  
negative.code:   command/2,
    sync_command/4,
    ensure_index/3
    , prepare_and_assign/1]).
  
  
  -type cursorid() :: integer().
  