message: Clarify return type for defun as zero or more `tf.Tensor`s.
diff: @@ -716,8 +716,7 @@ def defun(func):
  objects. Non-Tensor python objects are treated as constants, and new function
  definitions are created internally based on their values.
  - func must return a tf.Tensor (NOT a Tensor) or a list of tf.Tensor (NOT a
  - Tensor).
  + func must return zero or more `tf.Tensor`.
  Control flow constructs (e.g., `if`, `while`) are not yet compatible with
  `defun`.
  @@ -748,7 +747,7 @@ def defun(func):
  Returns:
  A callable that will execute the compiled function (and return zero
  - or more Tensor objects).
  + or more `tf.Tensor` objects).
  """
  # TODO(apassos): deal with captured global state. Deal with control flow.
  try:
  