tree a99bf87fc56e32e48a135aa18b1cccc094c06e75
parent dc4394c6d3b9e9807fe715d4086a504cc98e93a0
author Sho SHIMIZU <sshimizu@us.fujitsu.com> 1454117947 -0800
committer Ray Milkey <ray@onlab.us> 1454171621 +0000

Use more concrete type for return value

Same resources are not allowed for a parent and Set is more suitable than
Collection

Change-Id: Ib45179819d81376678bf8949864b12b5bd721085