message: Export feature importance for oblivious tree nodes.
diff: @@ -196,6 +196,10 @@ def convert_to_universal_format(dtec, sorted_feature_names,
  matching_id = categorical_test.value.add()
  matching_id.int64_value = split.feature_id
  node.custom_left_child_test.Pack(categorical_test)
  + elif (node_type == "oblivious_dense_float_binary_split" or
  + node_type == "oblivious_categorical_id_binary_split"):
  + raise ValueError("Universal tree format doesn't support oblivious "
  + "trees")
  else:
  raise ValueError("Unexpected node type %s" % node_type)
  node.left_child_id.value = split.left_id
  @@ -229,6 +233,13 @@ def _get_feature_importances(dtec, feature_names, num_dense_floats,
  split = tree_node.categorical_id_binary_split
  split_column = feature_names[split.feature_column + num_dense_floats +
  num_sparse_float]
  + elif node_type == "oblivious_dense_float_binary_split":
  + split = tree_node.oblivious_dense_float_binary_split
  + split_column = feature_names[split.feature_column]
  + elif node_type == "oblivious_categorical_id_binary_split":
  + split = tree_node.oblivious_categorical_id_binary_split
  + split_column = feature_names[split.feature_column + num_dense_floats +
  + num_sparse_float]
  elif node_type == "categorical_id_set_membership_binary_split":
  split = tree_node.categorical_id_set_membership_binary_split
  split_column = feature_names[split.feature_column + num_dense_floats +
  