anchor.diff:                    ChildSpec = {Id,
                                  {leo_backend_db_server, start_link, Args},
                                  permanent, 2000, worker, [leo_backend_db_server]},
  -                  case supervisor:start_child(leo_backend_db_sup, ChildSpec) of
  +                  case supervisor:start_child(SupRef0, ChildSpec) of
                         {ok, _Pid} ->
                             Id;
                         Cause ->
  
positive.code:              atom()).
  backend_mod(bitcask) ->
      leo_backend_db_bitcask;
  backend_mod(leveldb) ->
      leo_backend_db_eleveldb;
  backend_mod(ets) ->
      leo_backend_db_ets;
  backend_mod(_) ->
  
negative.code: %%
  %%
  -spec(start_child(atom(), pos_integer(), atom(), string()) ->
               ok | true).
  start_child(InstanceName, NumOfDBProcs, BackendDB, DBRootPath) ->
      start_child(?MODULE, InstanceName, NumOfDBProcs, BackendDB, DBRootPath).
  
  start_child(SupRef0, InstanceName, NumOfDBProcs, BackendDB, DBRootPath) ->
      BackendMod = backend_mod(BackendDB),
      Fun = fun(DBNumber) ->
                    {Id, StrDBNumber} =
  