improve TSequentialExecutor's documentation
improve TSequentialExecutor's documentation

olifre/root,root-mirror/root,olifre/root,root-mirror/root,root-mirror/root,root-mirror/root,root-mirror/root,root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,olifre/root,root-mirror/root,root-mirror/root,olifre/root,root-mirror/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root