message: remove duplicate parameter value checks
diff: @@ -104,18 +104,6 @@ def group_by_window(key_func,
  ValueError: if neither or both of {`window_size`, `window_size_func`} are
  passed.
  """
  - if (window_size is not None and window_size_func or
  - not (window_size is not None or window_size_func)):
  - raise ValueError("Must pass either window_size or window_size_func.")
  -
  - if window_size is not None:
  -
  - def constant_window_func(unused_key):
  - return ops.convert_to_tensor(window_size, dtype=dtypes.int64)
  -
  - window_size_func = constant_window_func
  -
  - assert window_size_func is not None
  def _apply_fn(dataset):
  """Function from `Dataset` to `Dataset` that applies the transformation."""
  