How do you split the COCO 5k test images into 1K?

[pengzhanguestc]

I found 5k images in coco test set.And in paper you got results on 1k test image.I found no corresponding code about spliting the 5k coco test set. So did you make the 1k test set according to some protocol or just by random sampling from the 5k test set?And could you please offer relevant codes