how to get 'mean' and 'std' of isic18?

[DumbGuy-AI]

class myNormalize:
def init(self, data_name, train=True):
if data_name == 'isic18':
if train:
self.mean = 157.561
self.std = 26.706
else:
self.mean = 149.034
self.std = 32.022
I wonder to konw how to calculate maen and std with specific code.I need some help,plz.