}
  }

  // Verify variable_arg_indices is sorted in ascending order.
  int64_t prev_index = -1;
  for (auto arg_index_attr : getVariableArgIndicesAttr()) {
    if (!mlir::isa_and_nonnull<mlir::IntegerAttr>(arg_index_attr)) {
      return emitOpError() << "variable_arg_indices must be an integer";
    }