Build the mask dataset to indicate which element to skip.

  Args:
    mask: `tf.Tensor`, binary mask to apply to all following elements. This
      mask should have a length 100.
    mask_offset: `tf.Tensor`, Integer specifying from how much the mask
      should be shifted for the first element.

  Returns:
    mask_ds: `tf.data.Dataset`, a dataset returning False for examples to skip
      and True for examples to keep.

def _build_mask_ds(mask, mask_offset):
  """Build the mask dataset to indicate which element to skip.

  Args:
    mask: `tf.Tensor`, binary mask to apply to all following elements. This
      mask should have a length 100.
    mask_offset: `tf.Tensor`, Integer specifying from how much the mask
      should be shifted for the first element.

  Returns:
    mask_ds: `tf.data.Dataset`, a dataset returning False for examples to skip
      and True for examples to keep.
  """
  mask_ds = tf.data.Dataset.from_tensor_slices(mask)
  mask_ds = mask_ds.repeat()
  mask_ds = mask_ds.skip(mask_offset)
  return mask_ds