message: Fix off-by-one documentation error.
  sequence_lengths is the actual length of the sequence and therefor should not be used as zero-based indexing.
  The code is correct but the documentation was misleading.
diff: @@ -178,7 +178,7 @@ def select_last_activations(activations, sequence_lengths):
  """Selects the nth set of activations for each n in `sequence_length`.
  Reuturns a `Tensor` of shape `[batch_size, k]`. If `sequence_length` is not
  - `None`, then `output[i, :] = activations[i, sequence_length[i], :]`. If
  + `None`, then `output[i, :] = activations[i, sequence_length[i] - 1, :]`. If
  `sequence_length` is `None`, then `output[i, :] = activations[i, -1, :]`.
  Args:
  