message: Enable autograph by default in defun.
diff: @@ -724,7 +724,7 @@ class PolymorphicFunction(object):
  name,
  input_signature=None,
  attributes=None,
  - autograph=False):
  + autograph=True):
  """Initializes a polymorphic function.
  Args:
  @@ -1137,7 +1137,7 @@ def validate_signature(signature):
  "a possibly nested sequence of TensorSpec objects.")
  -def defun(func=None, input_signature=None, autograph=False):
  +def defun(func=None, input_signature=None, autograph=True):
  """Compiles a Python function into a callable TensorFlow graph.
  `defun` (short for "define function") trace-compiles a Python function
  @@ -1470,7 +1470,7 @@ def defun(func=None, input_signature=None, autograph=False):
  def defun_with_attributes(func=None,
  input_signature=None,
  attributes=None,
  - autograph=False):
  + autograph=True):
  """Compiles a Python function into a callable TensorFlow graph.
  This function supports adding extra function attributes. See detailed
  