message: singleton fix
diff: @@ -46,7 +46,7 @@ namespace eosio {
  T get_or_create( account_name bill_to_account, const T& def = T() ) {
  auto itr = _t.find( pk_value );
  return itr != _t.end() ? itr->value
  - : _t.emplace(bill_to_account, [&](row& r) { r.value = def; });
  + : _t.emplace(bill_to_account, [&](row& r) { r.value = def; })->value;
  }
  void set( const T& value, account_name bill_to_account ) {
  