def test_function_with_fancy_docstring(arg):
  """Function with a fancy docstring.

  Args:
    arg: An argument.

  Returns:
    arg: the input, and
    arg: the input, again.

  @compatibility(numpy)
  NumPy has nothing as awesome as this function.
  @end_compatibility

  @compatibility(theano)
  Theano has nothing as awesome as this function.

  Check it out.
  @end_compatibility

  """
  return arg, arg