// do not need to validate sparse_values.
  auto sparse_types_count =
      std::distance(op.getSparseTypes().begin(), op.getSparseTypes().end());
  if (op.getNumSparse() != sparse_types_count) {
    return op.emitError() << "attribute 'num_sparse' should be the same as "
                          << "the length of attribute 'sparse_types'";
  }