Image Preprocessing: Question about Normalize mean and std values.

In the source code `train_placesCNN.py`, can someone explain me how the values at
```
normalize = transforms.Normalize(mean=[0.485, 0.456, 0.406],
std=[0.229, 0.224, 0.225])

```
were obtained?

This values represent the mean and std RGB channel values for the whole Places 365 dataset?
They are the same values of ImageNet dataset provided by PyTorch.
This is correct or they should be the mean and std RGB channel values for Places dataset?

Thank you.