about the "get_free_gpus()" function

[Wang-Zeyu]

EEND/eend/chainer_backend/utils.py

Line 40 in b851eec

del gpus[busid]

when there are 2 process running on the same GPU IDs，the "del gpus[busid]" will raise key error.

[DiLiangWU]

If there are 2 process running on the same GPU IDs, You should change the code here. First determine whether the key exists in gpus now. If exist, then delete,otherwise do nothing. This way, the second attempt to delete won't raise key error.