code: def test_many_metrics(self):
      self._run_test(self.train, self.test, self.test_metrics)
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import unittest
  import turicreate
  from turicreate.toolkits._main import ToolkitError
  import random
label_desc: Use image node_id 8 for calling the TreeRegressionTrackingMetricsTest obj's underlying member method code with example usage: obj.test_many_metrics() without return types