import.
*   Breaking change to `tf.contrib.data.Dataset` APIs that expect a nested
    structure. Lists are now converted to `tf.Tensor` implicitly. You may need
    to change uses of lists to tuples in existing code. In addition, dicts are
    now supported as a nested structure.

## Changes to contrib APIs

  }];

  let description = [{
embedding_indices[i] and aggregation_weights[i] correspond
to the ith feature.

The tensors at corresponding positions in the three input lists (sample_indices,
embedding_indices and aggregation_weights) must have the same shape, i.e. rank 1
with dim_size() equal to the total number of lookups into the table described by
the corresponding feature.
  }];