def lr_decay(optimizer, lr_now, gamma):
    lr = (lr_now * gamma)
    for param_group in optimizer.param_groups:
        param_group['lr'] = lr
    return lr
def lr_decay(optimizer, lr_now, gamma):
    lr = (lr_now * gamma)
    for param_group in optimizer.param_groups:
        param_group['lr'] = lr
    return lr