code: public void withConnection(StatementRunnable runnable, Object argument) {
          Connection connection = null;
          try{
              connection = open();
  
              runnable.run(connection, argument);
          } catch (Throwable t) {
              throw new Sql2oException("An error occurred while executing StatementRunnable", t);
          } finally{
              if (connection != null) {
                  connection.close();
              }
          }
      }
docs: Invokes the run method on the {@link org.sql2o.StatementRunnableWithResult} instance. This method guarantees that
  the connection is closed properly, when either the run method completes or if an exception occurs.
  @param runnable
  @param argument