message: Update debugger.md
  Fix issue of "function object is not subscriptable" in sample code.
diff: @@ -781,7 +781,7 @@ sess.run(b)
  ``` python
  import numpy as np
  -a = tf.Variable(np.ones[10], name="a")
  +a = tf.Variable(np.ones(10), name="a")
  b = tf.add(a, a, name="b")
  sess = tf.Session()
  sess.run(tf.global_variables_initializer())
  