MNIST Normalization numbers

HI Team,

Need help with normalization . I was looking at the MNISt example and found transforms.Normalize((0.1307), (0.3081).

I understand how normalization works. But I want to know how come we concluded (0.1307 and 0.3081
Is there a better way of finding it.

These stats (mean and std) are calculated from the training dataset of MNIST offline and passed to transforms.Normalize.