anchor.diff:           {NewDB::db(), Status::ok | failed}.
   
   -spec get_locks(DB::db(), Key::key()) ->
  -         {DB::db(), {WriteLock::boolean(), ReadLock::integer(), Version::version()} | failed}.
  +         {DB::db(), {WriteLock::boolean(), ReadLock::integer(), Version::version()} | {true, 0, -1} | failed}.
   
   -spec read(DB::db(), Key::key()) ->
            {ok, Value::value(), Version::version()} | {ok, empty_val, -1}.
  
positive.code: -spec get_middle_key(DB::db()) -> {ok, MiddleKey::key()} | failed.
  
  -spec split_data(DB::db(), MyKey::key(), HisKey::key()) ->
           {NewDB::db(), [{Key::key(), {Value::value(), WriteLock::boolean(), ReadLock::integer(), Version::version()}}]}.
  
  -spec get_data(DB::db()) ->
           [{Key::key(), {Value::value(), WriteLock::boolean(), ReadLock::integer(), Version::version()}}].
  
  -spec add_data(DB::db(), [{Key::key(), {Value::value(), WriteLock::boolean(), ReadLock::integer(), Version::version()}}]) ->
           NewDB::db().
  
negative.code:          NewDB::db().
  
  -spec get_version(DB::db(), Key::key()) ->
           {ok, Version::version() | -1} | failed.
  
  -spec delete(DB::db(), Key::key()) ->
           {NewDB::db(), Status::ok | locks_set | undef}.
  