code: @Override
      public void returnConnection(Connection conn) {
          try {
              if (conn instanceof MyConnectionInvocationHandler) {
                  DbcHelper.returnConnection(((MyConnectionInvocationHandler) conn).target);
              } else {
                  DbcHelper.returnConnection(conn);
              }
          } catch (SQLException e) {
              throw new DaoException(e);
          }
      }
docs: {@inheritDoc}