def lr_decay(optimizer, epoch, decay_rate, init_lr):
    lr = (init_lr / (1 + (decay_rate * epoch)))
    print(' Learning rate is set as:', lr)
    for param_group in optimizer.param_groups:
        param_group['lr'] = lr
    return optimizer
def lr_decay(optimizer, epoch, decay_rate, init_lr):
    lr = (init_lr / (1 + (decay_rate * epoch)))
    print(' Learning rate is set as:', lr)
    for param_group in optimizer.param_groups:
        param_group['lr'] = lr
    return optimizer