which one is the checkpoint?

Thanks for your codes and model. I want to download the i3d model pre-trained on the Kinetics dataset but feel confused about the checkpoint. I followed the path in evaluate_sample.py
_CHECKPOINT_PATHS = {
'rgb': 'data/checkpoints/rgb_scratch/model.ckpt',
'rgb600': 'data/checkpoints/rgb_scratch_kin600/model.ckpt',
'flow': 'data/checkpoints/flow_scratch/model.ckpt',
'rgb_imagenet': 'data/checkpoints/rgb_imagenet/model.ckpt',
'flow_imagenet': 'data/checkpoints/flow_imagenet/model.ckpt',
}
I copied the checkpoints folder to a new path and tried to load it.
However, is seems that no such file or directory: 'checkpoints/rgb_scratch_kin600/model.ckpt'
I found 4 files under the folder rgb_scratch_kin600 but cannot find the model.ckpt. Could anyone help me?
Besides, can the checkpoint be loaded to model writing in Pytorch?