Revert "print list return value"
Revert "print list return value"

This reverts commit 9bbd5328cbd734907fe9762b9a1c3cf9fc069d54.

yvxiang/coverage_for_bfs,lylei/dfs,bluebore/dfs,bluebore/bfs,myawan/bfs-1,bluebore/bfs,yvxiang/dfs,bluebore/dfs,00k/ToyDFS,bluebore/bfs,yvxiang/coverage_for_bfs,linyvxiang/dfs,yvxiang/dfs,linyvxiang/dfs,yvxiang/dfs,yvxiang/coverage_for_bfs,lylei/dfs,bluebore/dfs,baidu/bfs,myawan/bfs-1,lylei/dfs,baidu/bfs,yvxiang/coverage_for_bfs,lylei/dfs,00k/ToyDFS,linyvxiang/dfs,myawan/bfs-1,myawan/bfs-1,baidu/bfs,yvxiang/dfs,baidu/bfs