message: Fix typo (undefined variable `mean_absolute_error`, should refer to `error` previously defined).
diff: @@ -64,7 +64,7 @@ sess.run(tf.local_variables_initializer())
  for batch in range(num_batches):
  sess.run([update_op_acc, update_op_error])
  -accuracy, mean_absolute_error = sess.run([accuracy, mean_absolute_error])
  +accuracy, error = sess.run([accuracy, error])
  ```
  Note that when evaluating the same metric multiple times on different inputs,
  