message: Fixes false-positive in tf.enable_eager_execution
  Simply using ops which have name scopes and other things will trigger
  adding a graph to the stack.
diff: @@ -5464,8 +5464,8 @@ def enable_eager_execution(config=None, device_policy=None,
  # pylint: disable=protected-access
  if context._default_mode == context.GRAPH_MODE:
  graph_mode_has_been_used = (
  - _default_session_stack.stack or
  - _default_graph_stack._global_default_graph is not None)
  + _default_session_stack.stack
  + or len(get_default_graph().get_operations()) > 0) # pylint: disable=g-explicit-length-test
  if graph_mode_has_been_used:
  raise ValueError(
  "tf.enable_eager_execution must be called at program startup.")
  