anchor.diff:              {DB, ok};
           [{Key, {_Value, false, _ReadLock, _Version}}] ->
               {DB, failed};
  -        [] ->
  -            {DB, failed}
  +        [] -> {DB, failed}
       end.
   
   %% @doc sets a read lock on a key
  
positive.code:         [{Key, {Value, WriteLock, ReadLock, Version}}] ->
              ?ETS:insert(DB, {Key, {Value, WriteLock, ReadLock - 1, Version}}),
              {DB, ok};
          [] ->
              {DB, failed}
      end.
  
  %% @doc get the locks and version of a key
  
negative.code:         [{Key, {_Value, false, 0, _Version}}] ->
              ?ETS:delete(DB, Key),
              {DB, ok};
          [{Key, _Value}] -> {DB, locks_set};
          [] -> {DB, undef}
      end.
  
  %% @doc reads the version of a key
  