TensorFlow 1.9 has Arrived!
https://towardsdatascience.com/tensorflow-1-9-has-arrived-1e6e9171ce5e
At the time of writing this article TensorFlow 1.9 is not on updated their official website but released on their GitHub.
Replace variable_scope('', ...) by variable_scope(tf.get_variable_scope(), ...) if you are opening variable scopes.