code: def test_submetric_tracking(self):
      # Plain attr
      metric = ExampleMetric(name="mse")
      metric.submetric = ExampleMetric(name="submse")
      self.assertEqual(len(metric.variables), 4)
  
      # In list
      metric = ExampleMetric(name="mse")
      metric.submetrics = [
          ExampleMetric(name="submse1"),
          ExampleMetric(name="submse2"),
      ]
      self.assertEqual(len(metric.variables), 6)
  
      # In dict
      metric = ExampleMetric(name="mse")
      metric.submetrics = {
          "1": ExampleMetric(name="submse1"),
          "2": ExampleMetric(name="submse2"),
      }
      self.assertEqual(len(metric.variables), 6)
  
imports: import numpy
  from keras import backend
  from keras import initializers
  from keras import metrics
  from keras import ops
  from keras import testing
  from keras.metrics.metric import Metric
label_desc: Use image node_id 5 for calling the MetricTest obj's underlying member method code with example usage: obj.test_submetric_tracking() without return types