code: def test_list_in_list(self):
      metric = MetricList(["acc", MetricList(["loss"])])
      self.assertTrue(metric.metric_list[0].name == "acc")
      self.assertTrue(metric.metric_list[1].name == "loss")
  
imports: import unittest
  from mock import Mock
  from torchbearer.metrics import MetricList, Metric, MetricTree, AdvancedMetric
label_desc: Use image node_id 1 for calling the TestMetricList obj's underlying member method code with example usage: obj.test_list_in_list() without return types