About BachNorm Layer

[moondaiy]

Hi, In tensorflow, when using bach norm layer , we need to updata moving_mean and moving_vairous, so we need use this operation
update_ops = tf.get_collection(tf.GraphKeys.UPDATE_OPS)
with tf.control_dependencies(update_ops):
train_op = optimizer.minimize(loss)
but in the code i do not find this operation. Could you tell me why???