title: Tensorflow graph fetch all consts in a scope
body: <p>I create a graph and now I want to fetch their ops, how can I do this?</p>
  
  <pre><code>g = tf.Graph()
  
  with g.as_default():
      # Define inputs
      with tf.name_scope("inputs"):
          a = tf.constant(2, tf.int32, name="a")
          b = tf.constant(3, tf.int32, name="b")
  
      # Ops
      with tf.name_scope("ops"):
          c = tf.multiply(a, b, name="c")
          d = tf.add(a, b, name="d")
          e = tf.subtract(c, d, name="e")
  
  sess = tf.InteractiveSession()
  
  _c, _d, _e = ... &lt;-- (I need some code here!)
  </code></pre>
  
  <p>Can you show me document links about this?</p>